Milo will quickly move 20ft west to hit the one due west of him. He swings fast with his rapier, relying on speed over strength to get a deep cut, channelling the anger and pain the same species caused him in the future (oh I do love messing with tenses during time shenanigans). If the first hit kills it, he will move south to the second one.

Attack 1: 16 to hit, 12 damage,
Attack 2: 16 to hit, 10 damage.

He then moves back to his starting position (or as close to it as he can get with 40ft movement total if he moved to engage the second one), not triggering any AoO due to Mobile feat.

With a heavy swing, Inge cuts off another creature's head. The body once again immediately slumps down to the ground as if a string controlling it has been cut and bursts into a pile of ash and broken bones. Inge tries to make another pass at the already injured creature she stops with the momentum of her first swing, but the the sudden dispersal of the other creature makes her stumble. Fortunately, Wadi makes up the fumble and finishes the creature away. The body falls heavily and shatters into bone fragments and melted puddles of flesh and blood. 

With rage, Milo leaps over one of the creatures before him and jams both of his rapier into its eye sockets. When the creature still struggles under him, he pulls out one and stabs it again. The creature shivers before its flesh melts away, leaving behind a fully intact skeleton and a puddle of blackened liquid. 

Myrla and Brix, who are hanging back a bit, can see that the battle will not be as easy. While they manage to kill the creature quickly, more are coming. The phalanx appears to be having a hard time blocking all the creatures. Some still manage to jump through the shield walls into the encampment. Another ten just made the jump and will reach melee distance soon. 

Despite having a target, the creature near Milo keeps running to the east. The same can be said with the north and southmost creatures, completely ignoring the druids and the defending group. 

LG1, LG2, LG6, and LG7 are still uninjured. 
LG3, LG4, and LG5 are dead. 

LG1 and LG6 will use the Dash action to the east. 

{{Another ten are approaching, they will appear at the edge of the map at the end of the round. Brix and Myrla, both of you are up. Currently, there is no creature in melee range from both of you.}}

{{Edit: Just saw the map again and technically Wadi wouldn't be able to attack the creature close to Inge. You're 15 feet short of movement. But, I will allow it just this time because it could be argued that the creature could be in the range of Wadi while it surrounds Inge.}}

Myrla notices how the creatures clearly ignore the druids and their ritual. She had expected, that they were ordered to defend them because they were in danger but it seems that the goal of these strange enemies is another. „What are they after?“ she cries to anyone listening her and glances eastwards trying to see what could be there in terms of a strategic target. Then, she dashes to the one most North and East (LG1) and places herself so that the next one will also have to pass by her. Seeing how more of them arrive, her determination slightly falters and she wonders if they actually have a chance to do anything of note here. After all they were brought into the scene to observe, quite likely, a calamity. 

Action: dash
Move: behind LG1, some 5 feet away from the tents to block the way for LG2.
Reaction: should LG1 move out of her range or LG2, the AoO is in the spoiler. Note that anyone hit by her AoO gets their speed reduced to 0, due to the Sentinel feat.

Brix will load a stone in his sling and ready an attack should one of the creatures present themselves as a target in range. 

(I couldn't see the map but I'm assuming that LG7 will be moving east and will show themselves at some point)

Rolled on sheet.

Attack=12

Damage=6

{{The following map is what the position looks like at the start of the new round. Myrla, I hope I do your position justice, but let me know if you don't like it. Brix, if you want to move before readying an action, you can hit LG6 with that roll.}}

{{At the end of the last round, 10 more of the creatures appear on the map. I've numbered them to make it easy. Just to make it simple, I'm going to just separate the round into 5 sections. The first section will now be LG2, LG7, LG16, and LG18. Second section: Inge, Wadi, Milo. Third section: LG1, LG6, LG11, LG12, LG13, LG17, LG20. Fourth section: Myrla, Brix. Fifth section: LG14, LG15, LG19. Seems daunting, but you still haven't been attacked yet somehow. Something is definitely going on here.}}

Myrla's quick reaction stops one of the creatures near her in its place before it can run away past her while keeping the attention of the other. It is rather worrying that more and more of those creatures are coming. 

One of the newly arrived creatures continues its stride and beelines directly toward Milo. It rears its claws, but Milo manages to back away without much effort. However, another creature beside it runs past Milo as if it doesn't see him.

LG2 uses Dash, but Myrla's AoO pops off and it's speed is reduced to 0.
LG7 and LG18 uses the Dash action directly to the east.
LG16 moves 30 ft. to Milo and uses Claw: 9 to hit [Miss]

{{Inge, Wadi, Milo, your turn.}}

Wadi would continue up to Inge and attack #2. 

Attack: 18 Damage: Unable to parse dice roll.

Bonus Action - Polearm Master Attack: 8 Damage: 5

{{With Wadi's attack, LG2 is down.}}

Seeing Myrla being crowded in, Wadi moves to help. His first swing misses as the creature appears nimbler than expected, but his backswing crashes on the creature's back. A crack echoes before the creature slumps to the ground. It twitches as its skin melts away, leaving behind its skeleton. There is a noticeable fracture on the skeleton's spine where Wadi must have hit it. 

Inge wheels, looking for a new target of her Rage.  Trusting Myrla and Wadi to handle LG1 and the other northern attackers, she lopes thirty feet south and five feet southwest to take up a defensive position against the more numerous southern ones.  Just out of range (15') of LG6 for her glaive, she instead holds her polearm in one hand, drawing and throwing two handaxes instead at LG6.

It occurs to her that the enemies seem intent on something beyond them and the druids, to the east, but she cannot wrap her mind around it.

Movement (35'):  Inge trots 30' south and 5' southwest to a point 15' north and 5' west of LG6.

Action:  Inge throws a handaxe at LG6.
Thrown handaxe to hit:  23
Thrown handaxe damage:  5 (min - ugh!) slashing - Rage does not add to thrown weapon damage.

Bonus Action:  Inge throws her second handaxe at LG6.
Off-hand thrown handaxe to hit:  9
Off-hand thrown handaxe damage (straight 1d6):  2 slashing - Rage does not add to thrown weapon damage.

Inge's battle-cry twists in frustration as she hefts her glaive once more, ready to face the southern marauders behind Milo.  She will use her Polearm Master opportunity attack on any enemy that enters the 10' reach of her glaive:

Possible Reaction (Polearm Master AoO) if any enemy approaches within 10' of Inge:
Glaive to hit:  14
Glaive damage:  7 + 2 from Rage = 9 slashing

Milo is really uneasy at the fact that the creatures, who devastated his home with no mercy, are just walking past ignoring them. But then one tried to hit him and without even noticing it, he stepped back, suddenly snapping back to the past-present. Clearly these things could see them, they were just choosing not to. This made it even more confusing. He shouts out to the leader, or anyone else that might be around and not doing a ritual "What is east of here. What is their target?"

While waiting for a response, he attempts to finish off LG16 after it attacked him. Attack 1: 11 to hit (probably miss), for a maybe 10 damage (piercing), followed up with his second attack of 20 to hit, and a measly 5 piercing.

{{I will assume Brix's is keeping the ready action instead of moving and attacking. That means it will pop off when LG7 dashes. Just to make it clear that you don't have a reaction anymore because LG6 will dash past you.}}

The first handaxe embeds deep on the LG6's side, yet it keeps running. Inge releases another, but the creature proves agile enough to move away from the flying handaxe. As she waits for another opportunity to attack the creature, she can feel two of the newly arrived creatures looking straight at her. It is quite strange as LG6 still ignores her and continues its stride to the east as if Inge is not there at all. 

There is no reply to Milo's question. It could be that no one hears it among the loud sound of crashing shields and clashing blades. Yet, as Milo follows up his first failed attack on LG16, he looks back and catches the gaze of the general. She doesn't speak or move, but there is a slight tilt to her head that is barely visible. There is a hint of worry in her eyes. He follows her direction and sees the line of wizards and sorcerers who are still standing in place behind the protective barrier. Their backs are to the battle currently happening, and they appear to be focusing intently at maintaining the barrier. The field beyond the barrier is smouldering with intense heat and the blackened smoke of the burnt field batters the barrier like the ebb and flow of the ocean's tide.

The two creatures eyeing Wadi rush to crowd him. Another one beelines toward Inge, while two others on the south side dashes through the tent, ignoring Milo completely. 

LG1, LG6, LG17, and LG20 use the Dash action to the east. 
LG11 and LG12 use the Dash action to crowd around Wadi.
LG13 uses the Dash action to beeline toward Inge. 

{{Brix and Myrla, it's your turn. So far this round, only LG2 is killed. If it's hard to keep track of the movement because of the many creatures involved in the combat, I'll mention the closest target to you. For Myrla, LG1 is 55 feet to your east, and LG11 and LG12 are 10 feet to your west. For Brix, LG6 is 15 feet to your east, and LG7 is 20 feet directly south of your position.}}

{{To my count there are a couple of reactions pending, and I thought I post it so we don't forget:

1. LG 17 would pass through Milo's range and trigger an AoO.
2. LG11 and LG12, both trigger AoO by Wadi for entering his range.
3. LG13 enters Inge's range and triggers an AoO (for this we already have the rolls).}}

Myrla looks after the escaping creature and evaluates the situation. On one hand she doesn't know why they run east and there are plenty more coming which she could and should turn her attention to, but on the other hand she feels she should not allow them to reach whatever they are after. It seems important to them. More important than their existence. "Hold them off a sec, Wadi! I'll get the runner!" Myrla shouts and sprints after the the creature (LG1). Her shield weighs heavy and it really isn't made to run up and down the battlefield with it in hand. Puffing she closes in at the creature and looks for an opportunity to thwart its mission while regretting to have chosen the shield over her longbow. (reactionary attack in spoiler if it tries to move away from her.)

Wadi seeing the two rush towards him spins around and quickly reacts to being crowded and thumps the first one arrive on his mellon (head). "Don't crowd me."

Polearm Master - Reaction to someone coming into my space (23 to hit but only 4 damage) to the first one to arrive near Wadi.

(Wadi would only get one of those as you only get one reaction, but other than that I agree. Here is Milo's AoO assuming it is valid)

Brix takes stock of what is happening and realizes that he is severely separated from his best possible protection. He sets his sling spinning, focuses in the creature 15ft from him, (LG6) and lets his magic stone fly. (FUMBLE!! 1 rolled via sheet.)

Not even bothering to see if the stone comes close to its mark, Brix sprints north as fast as his little gnome legs will carry him. (25ft)

{{Good pointing out by Myrla. Wadi and Milo get AoO for LG11 and LG17. Inge's unfortunately doesn't pop off because LG13 is still too far away from her new position even with a dash and LG17 is 15 feet away from her. However, LG14 is heading right at her and will trigger the AoO. Unfortunately, that means LG15 won't trigger it. Myrla's AoO for the next round has been noted.}}

As two creatures crowd around Wadi, he swings his polearm to make some distance and deter them. He manages to nail one (LG11) in its head, but the creature doesn't look too hurt by it.

At the same time, Milo takes his attention away from the creature before him when he notices another one (LG17) running past him. His rapier nicks the creature's neck, but it keeps running even with blackened ichor bursting and streaming down its neck and torso. 

As Brix shoots a stone with his sling and moves northward, he doesn't see that the stone veers way off and misses the creature (LG6) entirely. Still, the creature is not bothered. 

The rest of the creatures rush toward the east, with one (LG14) dashing right toward Inge. Fortunately, she is prepared and stops it right before it reaches her. It appears to be badly injured, but that is no indicator for these creatures as she has seen one still running off and fighting even with its head missing. She is not quick enough to fend off the next creature (LG15), but it appears to ignore her and runs past her. 

LG14 beelines and dashes to Inge before stopped short by her AoO.
LG15 and LG19 dash to the east, ignoring any creature they passes. 

Looking at the phalanx, it is clear that they are trying their best. It is holding and appears as if it can hold for hours, but some stragglers are still passing through into the encampment. some of the stragglers also appear to be more cognizant, gathering near each other as they rush toward the eastern side of the encampment. Another five is incoming toward the group and will be in melee range in a couple of seconds. 

{{Another group of five will enter at the end of the next round. So, this new round is free from additional enemies. The updated map for the end of the second round is here.}}

{{Start of a brand new round in a new post seems tidier.}}

Without anyone blocking it, LG7 dashes unopposed through the tents. Not far behind it, LG18 follows without stopping its stride even for a second. 

The one before Milo struggles in a push and pull with him. It claws at him with its deliberately sharpened bone claws, but Milo's small stature and quick feet are too agile for the creature. 

LG7 and LG18 are still dashing to the east. 
LG16 uses Claw: 8 to hit [Miss]

{{Inge, Wadi, and Milo, back to you. All of you regain your reaction.}}

Milo will try and kill the LG16 while with it, swinging twice.

Attack 1: 26, 14 damage (Sheet automatically rolled standard crit damage. I took the first roll of that (2) and then for the second I just changed it to be an 8 for crunchy crit)
Attack 2 (if required): 24, 5 damage.

He then will run 35ft to be south of LG15 (if the first attack kills LG16, the second attack will be on LG17 and he will run an additional 5ft as well. No AoO triggered as long as he makes an attack on them)

Wadi will swing about and try to hit LG11 again to the side of the head (21 to hit and 8 damage). He then swings back with the other end to strike again, but swings wide (7 to hit). 

Inge looks angrier about the ones that are getting away to the east than the ones she is fighting.

"You can still get them!  We got this, they go down easy." she shouts encouragement at her friends as she swings her glaive down at LG15 and then brings the haft around at LG14 who she had already hit (Polearm Master bonus attack).

Action:  Inge's main glaive attack on uninjured (?) LG15:
Glaive to hit:  22
Glaive damage (including Rage):  16 (max) slashing

Bonus Action:  Inge's glaive back-end Polearm Master bonus attack on LG14 who she had already injured with her previous opportunity attack.
Glaive back-end to hit:  19
Glaive back-end damage (including Rage):  10 (max) bludgeoning

Movement:  Hoping that her blows fell these two closest opponents (and taking an opportunity attack if LG15 is still up), Inge turns and gives chase to the enemies running east past them, moving thirty-give feet.  SE-->SE-->SE-->SE-->E-->E-->E

Possible Reaction later this turn:  As before, Inge will opportunistically attack any enemy that enters within the 10' reach of her Glaive.
Glaive AoO to hit:  20 (dirty)
Glaive AoO damage (including Rage):  14 slashing

Milo brings his rapier down toward LG16 again, severing its head from its neck. When the creature doesn't fall to the ground as expected, and remembering this same thing happened to him in the past, he quickly brings his other rapier to finish the creature. 

Bolstered by his friend's call, Wadi smacks the body of the creature before him, folding it into two as it crumbles to the ground in a pile of messy bone dust and gore. 

With a mighty swing, Inge spins her glaive in the air before bringing it down to the two surrounding her. The two creatures fall to the ground, one headless and the other bisected right in the middle of its torso. Bone fragments shatter across the ground as the creatures fall. As she looks up once again, she can see that four out of the five creatures that had bypassed the phalanx are now shifting their stride to head straight toward her. 

As the last creature Inge fell melts completely into a puddle, she swears she can see some of the bone fragments on the ground shuddering and moving. 

LG16, LG11, LG14, and LG15 are all down.

Updated inititive:LG7 & LG18; Milo, Wadi, Inge; LG1, LG6, LG12, LG13, LG17, LG20; Brix & Myrla; LG19

LG1 tries to continue its stride, but Myrla is ready to block its way. The creature tries to move through her, but she stands firm. Meanwhile, LG6 runs unopposed on the south side of the encampment. It is practically behind the line of wizards and sorcerers still focused on maintaining the barrier. 

When Wadi kills one of the creatures around him, one of the creatures that beelines toward Inge suddenly shifts its head toward Wadi and rushes toward him. With two around him, it becomes harder to fend off the creatures. It is as if they are coordinating their attack with each other. The larger their number, the more tactical and powerful their attacks become. He fends off one, but the other gets the better of him. As its sharpened claw rakes his body, Wadi feels something entering and coursing through his body. It makes him feel lethargic and heavy. Looking at the incoming creatures still a little away from him, he can see that one is eyeing and beelining directly toward him. 

When Milo turns around to move, he immediately notices that the creature that previously ignored him is now looking at him. It attacks as soon as it is close to him. Another one who is quite a distance away from him also suddenly turns and rushes toward him with its claw. Milo easily ducks and weaves around the flurry of claws. 

LG1 tries to dash but got stopped by Myrla's AoO. It is now standing still and doing nothing. Not even trying to attack. 
LG6 dash unoppossed. 
LG12 attacks Wadi with its Claws: 13 to hit. [Miss].
LG13 moves toward Wadi and attack with its Claws: (18, 8) with advantage from Pack Tactics. 6 slashing damage. Wadi must make a DC 10 Con save or become paralyzed
LG17 attacks Milo with its Claws: 6 to hit [Miss].
LG20 moves toward Milo and attack with its Claws: (5, 9) with advantage from Pack Tactics. [Miss]

{{Very nice rolls on yours, but not so on mine. Myrla and Brix, it's your turn.}}