OOC: Apologies,

Attack 1: 23 (28-5) Damage: 22 (12+10)

Attack 1 (D): 17 (22-5)

Attack 2: 25 (30-5) Damage: 18 (8+10)
Attack 2 (D): 11 (16-5)

Dread Ambusher Attack: 11 (16-5) Damage: 22 (12+10)

Dread Ambusher Attack (D): 12 (17-5)

Using Sharpshooter on all 3 attacks

So, one attack only hits - the first, for 22 damage.

The creatures attack:

C1 is attacking Bazavur, pincers snapping towards him. First attack is 12 against AC and misses, second attack is 21 against AC and hits for 15 points of piercing damage, and Bazavur is grappled. The tentacles that protrude from the creature's mouth seem to quiver in anticipation.

C2 is attacking Soar: First attack is a nat 20, 18 points of slashing damage and Soar is grappled. The tentacles writhe towards you and stroke your cheek; Soar must make a CON save, DC 13, or be paralyzed.

C3 is attacking Tobin: 9 against AC, and 10 against AC. The pincers snap harmlessly over Tobin's head.

C4 is following, and attacking, Varan: 13 against AC and 13 against AC, two misses again.

Soar and Tobin are up, but I will need Soar's CON save first. Bazavur is grappled, Soar is (possibly) paralysed, and C3 is looking close to its end.

Soar gasps in pain and is taken hold by the tentacles (CON save: 4+6=10)

Yikes.

So no actions, bonus actions, movement, or speech, as I read it. Nothin.

Not sure if she gets to repeat the save at the end of her turn, but if so: CON 8+6=14

Yes. you do. So you fail the initial save, but the effect only lasts a few seconds and you are free again.

Tobin is up.

Free of paralysis but still grappled?

(Steve I assume you didn’t halve the damage bazavur took before you posted so after his resistance to damage from rage he only takes 7 points? I assume there’s not a saving throw to avoid the grapple. Just a contested check to escape? Does that count as an action/bonus action? Movement? Or does it just happen? Edit: I asked before looking up the rules. They state it’s an action. In case someone else didn’t know. 😊)

"Keep those tentacles away from you, they paralyze you and I just barely got free!" Soar says in a slurred voice, recovering from... whatever it was.

Tobin:

Seeing his fellows in peril, Tobin quickly calculates relative positioning and carefully place a lightning ball centered to his southeast so it hits three of the creatures (and the water they are swimming in).   

Fireball-> Lightning Ball (and hoping this is saltwater for good conduction):  C1, C3, and C4–DC 20 Dexterity Save for Half:  32 Lightning Damage

(I didn't halve the damage in the post, but please halve on your character sheet, yes. An attempt to escape the grapple is an attack action, so if you have two attacks in a turn, you can make two attempts. You can still attack while grappled, though, if you prefer.)

All three creatures fail their saving throws as lightning engulfs them and sparks scatter across the surface of the whole pool. C3 and C4 are shocked to death, their corpses dropping and floating on the water. C1 is badly hurt too.

Round Three:
Bazavur, Varan and Aiwin
C1 and C2
Soar and Tobin

Bazavur, Varan and Aiwin are up. Bazavur is grappled.

Bazavur being grappled by one of the large creatures lashes out recklessly at the one not currently bobbing lifelessly in the water. (First attack:22&26 to hit 16 damage. Second attack: 14&28 to hit 13 damage. Using reckless, attacks against me have advantage. Attacking C2) 

“Someone get this creature off of me.” He bellows angrily. 

"Nice shot Tobin!" Varan exclaims. "I would Baz, but I don't have anything at the moment." Varan says as he plants his feet and pulls back the string on his bow, "But with some luck this will give someone a boost." A glowing light takes the place of where an arrow would be notched on the bowstring; and he says, "Alright, Lady Luck, my new comrades could use some help with this creature." He lets the bowstring go as he casts [spell[guiding bolt[/spell].

Acton: Casts guiding bolt on C1, Attack: 19, Damage: 16 radiant. If the creature is hit the next attack roll made against this target has advantage; as it sparkles with mystical dim light that looks like floating coins. 
Movement: none.
Bonus Action: none

Varan's spell hits, and C1 is illuminated by a faint glow, and your hear the almost inaudible clink of coins - yes, next attack has advantage.

Bazavur's attacks have C2 pretty badly hurt, but not down yet.

Aiwin is up.

Aiwin draws three more arrows and fires them off at the creature diagonal of him (C2).

OOC:

Attack 1: 9 (14-5) *nat 1*

Attack 2: 27 (33-5) *nat 20* Damage: 24 (14+10)

Dread Ambusher Attack: 22 (27-5) Damage: 20 (10+10)

Using Sharpshooter on all 3 attacks

Aiwin, your first arrow hits a hedge - a little embarrassing, but you soon recover. The second and third finish off the poor creature, and it drops into the water like its fellows.

Only C1 remains. Does it know it's now alone? If so, it doesn't care. C1's tentacles now wrap around Bazavur's face. Bazavur, give me a CON save, DC13, and then if you pass, a second CON save.

Bazavur gets a +4 to all saves, still being within 10 feet of Soar, who would like nothing more than to gut these awful things.

Con save: (22 plus 4 from soar) 26

con save: (nat 1, 7plus 4 from soar) 11

Bazavur is paralyzed on the second attack. With the tentacles wrapped around his face, the creature pulls Bazavur into the water, down fifteen feet below the surface. Those on the left/west side of the pool have a clear line of sight to Bazavur because Tobin has made the water clear.

Soar and Tobin are up. 

Tobin:

Tobin squeaks as Bazavur is pulled underwater, “EEK!  Save him!”  With little he can do to directly help, Tobin conjures a lightning sphere just under the descending lobster, hoping to at least slow its descent until his allies can destroy it.

Flaming Sphere->Lightning Sphere:  DC 20 Dexterity Save for half:  5 shock damage

(How does drowning/holding your breath work again? Can I do that while paralyzed? Also, can bazavur see while paralyzed? If so, did he see anything else in the water?)