[Unfortunately, I think what you're describing is beyond the limitations of the spell.  Providing difficult terrain is one thing, but moving beyond their footprint to grab flying enemies out of the air would take something like an awakened plant.]

Cosette's crossbow bolt connects with the Vrock, though it completely ignores it, focused as it is on maintaining its grip on the slashing artificer.

Vrock 2 flies the last 20' (10' up, 10' over) to where Vrock 5 holds Grugga.

We finish this one... then we split up the meat and belongings!  A 2 way split is good, yes!?

Flanking Grugga, it attacks with beak and claw.

Beak Attack:  23  Damage:  10

Talons Attack:  22  Damage:  19

No, replies Vrock 5.  Mine!

1. Cosette
2. Vrocks (flock 1)
3. Leelan
4. Grugga
5. Aubrey
6. Raqisat
7. Vrocks (flock2)

Leelan continues to shoot at Vrock 5, hoping to finally make him drop his companion.

Attack 1: 22 Damage: 7

Attack 2: 18 Damage: 4

Slayer’s Prey: 4 (extra damage on the first attack that hits)

Grugga is able to withstand the onslaught of beaks and sharp claws... barely. Blood pours from  the sky as all the attacks against the artificer find their mark. Throughout this barrage of supernaturally sharp attacks, Grugga loses track of the battle below and whistles a generic command to Zap - "attack something close."

BA: Zap moves 5' to #4 and attacks. Attack: 21 Damage: 6 force

Then, grunting and gasping from the pain, he musters his last dregs of strength to heft his sword and try once again to cleave his way out of #5's grasp. If attack 1 kills, he'll use his second attack to grapple attempt #2.

Attack1: 12 to hit, 10 magical slashing

Attack 2: 20 to hit, 6 magical slashing

If he falls, he'll use his reaction to feather fall

Sensing the battle might possibly soon be won, Aubrey moves closer to the flock of demonic birds using the powers of his talisman to unleash another two golden beams of eldritch crackling force against the hexed Vrock.

Moving within 30 feet of Vrock 4.

Eldritch Blast: 20 Force: 5 Necrotic: 6
Eldritch Blast: 22 Force: 7 Necrotic: 1

(If any of the blasts hits Vrock 4, Aubrey uses his maddening Hex to cause 4 more psychic damage to Vrocks 4 and 5)

     Raqisat moves into melee with Vrock4 and attacks.  He can’t do much about the ones with some elevation at the moment so this one gets all his reckless fury… (Reckless attacks so he has adv but does have advantage attacking him)

Radiant Whip Attack:  13 to hit for 10 damage

offhand Scimitar Attack:  19 to hit for 9 damage

     IF this Vrock is downed (by himself or Aubrey or whatever) then Raqisat uses remaining movement to go to and start climbing the tree nearest the flying bickering Vrocks…

Vrock 4, once again struck by Aubrey, diverts its attention from Raqisat.  It wheels on a dime and races back across the battlefield, ending its turn adjacent to Aubrey and Leelan.  [Both Raqisat and Zap can make AOO.]

Vrock 5, still grasping Grugga, makes another attack with its Beak as it holds him in its Talons.

Beak Attack:  21  Damage:  11  [This appears to be enough to render Grugga unconscious.  We will need a Death Save from Grugga next round unless something else interferes.]

Then, feeling him go limp, Vrock 5 lets him dangle, holding him by just one leg as he swings through the air.  Then it flies another 10' up and 10' east.

There... one is dead.  Go kill your own if you want meat.  This one is mine!

Round 6!

1. Cosette
2. Vrocks (flock 1)
3. Leelan
4. Grugga
5. Aubrey
6. Raqisat
7. Vrocks (flock2)

Status

• Aubrey:  1d8 Bardic Inspiration available
• Cosette: Concentrating on enhance ability, under the effect of 'Bears Endurance'
• Grugga: Grappled, 40' above the ground, Unconscious
• Leelan:  Concentrating on protection from evil and good, under the effect of Protection From Evil and Good
• Raqisat:  Raging, Under the effects of Protection From Poison, 1d8 Bardic Inspiration available

• Vrock 1:  Dead
• Vrock 2:  ~50%, 30' above the ground
• Vrock 3:  Dead
• Vrock 4:  ~50%, 5' above ground
• Vrock 5: ~25%, 40' above the ground

     Raqisat, frustrated with these damn flying foes, instinctively flashes out his whip towards the Vrock as it starts leaving combat with him.

Raqisat AOO on Vrock4:  26 to hit for 8 damage

     "Cowardly flying rat!" Raqisat calls out after the fleeing beast.

Leelan looks in horror as Grugga is knocked out by the Vrock. He needed to get over to him to help him. But before he had the chance to do anything, another one of these blasted bird stood in front of him and Aubrey. Leelan decided to trust in the power of his protective spell and move away from his original hiding place and try to pepper Vrock 5 with some more arrows.

Move: 3 hexes NE (taking the attack of opportunity at disadvantage)

Attack 1:  11 Damage: 6

Attack 2:  23 Damage: 8

Slayer’s Prey:  1 extra damage on the first attack that hits

(edit because it was showing dice rolls not yet available for this section. Had to adjust)

The blood loss was becoming unbearable, and, after receiving yet another monstrous blow through his armor, Grugga begins to lose consciousness... his head lolls back and his feet stop kicking, but hand never lets go of his weapon. In a start, he jolts back awake and yells "No! I will overcome these demons!"

racial ability: relentless endurance

Vrock 5 gives a surprised RAWK! as Grugga lurches back from the brink in its talons.  It drops him involuntarily.

(("Relentless Endurance. When you are reduced to 0 hit points but not killed outright, you can drop to 1 hit point instead. You can’t use this feature again until you finish a long rest." My understanding is that this is a free action. It doesn't say any type of action or reaction needed, and it doesn't show up under "actions" on my dndbeyond character sheet - moreover, on the traits it explicitly says "no action." If so, I think I still have my reaction this turn. However, I understand that Orcs in your world are not exactly the same as Half-Orcs in the rulebook, so if I'm incorrect let me know.))

Grugga is just as surprised as the Vrock as he's let go. His blood and thunder turns to sudden panic as he finds himself quickly falling after having just "woken up" from unconsciousness. Having considered it in advance though, the artificer is quick to react and he grabs a crystal out of a pocket and throws it to the quickly-approaching ground. The crystal shatters and reforms into a fragile quarter pipe, that catches the Orc and smoothly redirects downward momentum into sideways momentum, spitting him out ignobly but unharmed onto the mossy cobblestones of the long-forgotten plaza. Grugga manages to stand up, wheezing, despite the alarming amount of blood spattered on the stones.

reaction: feather fall

[No that's fine.  I had forgotten about Relentless Endurance in the previous post.  All that checks out.]

Thanks to his crystaline gadgetry, the grievously wounded Grugga is able to land safely on the ground.  

Meanwhile, Raqisat lashes Vrock 4, inflicting what looks like a painful red stripe down its back.

1. Cosette
2. Vrocks (flock 1)
3. Leelan (turn posted, outcome pending)
4. Grugga
5. Aubrey
6. Raqisat
7. Vrocks (flock2)

Cosette exhales a breath of relief when Grugga would gasp back to life. A smirk even tugs at her lips from the Vrocks surprise, and pulls even further when the artificer would fall with feathery grace. She whistles and calls out to the vrock. “‘Ey, give it up gas fer brains!”

Vs Vrock 5
Vicious Mockery Wisdom saving throw DC15 or take 7 psychic damage and have disadvantage on the next attack roll it makes before the end of its next turn.

Save:  5

Vrock 5 gasps at Cosette's mockery, shaking its head in distress.  

Vrock 2, meanwhile, observes the scene from above.  It looks hungrily at Grugga, but can't get to him faster than Vrock 5.  Likewise, Vrock 4 seems to have cornered the market on Leelan and Aubrey.  And while Cosette is a tempting target, it remembers those miserable, grasping trees she is hiding under.  With a sigh, it looks down at Raqisat, likely the least tender morsel available, and descends to attack.

Beak Attack:  19  Damage: 14

Talons Attack:  24  Damage:  17

Elsewhere, Leelan sidesteps Vrock 4 to launch arrows at Vrock 5.  These arrows connect, and Vrock 5 is looking really bad now.  At the same time, perhaps relying too much on his spell for protection, Leelan falls prey to the claws of Vrock 4.

AOO Talons Attack (at Disadvantage):  17  Damage:  11

The claws are hung up momentarily in an ether of light around Leelan... but then tear through to rake his back as he moves away.

1. Cosette
2. Vrocks (flock 1)
3. Leelan 
4. Grugga
5. Aubrey
6. Raqisat
7. Vrocks (flock2)

     Upon the first attack/hit from the Vrock, Raqisat uses his reaction to trigger his Radiant Weapon (whip) and attempt to blind the Vrock until the end of it's next turn.  The attacker must succeed on a DC 15 Con Save or is blinded after attack 1 until end of next turn... (Maybe that'll save Raq some damage?  Maybe not. First of 4 charges used.)

Concentration save on Protection from Evil and Good for Leelan: 16

(Spell is lost :( )

Vrock 2 CON save:  14

Vrock 2 flinches but is able to avert its eyes from the blinding luminosity of Raqisat's coiled rawhide.

Rolling out at a stumble from his crystalline quarter pipe, Grugga sets his sights on Vrock 4, hovering low to the ground and harassing Leelan and Aubrey with its wicked talons. The bookish and normally composed Grey Orc roars a wordless war cry and closes the gap to Vrock 4 in a few long strides. Displaying the ferocity his people are known for, he leaps into two-handed downward slash and then attempts to skewer the demonic bird with a powerful thrust.

Attack 1 (advantage from flanking, I think): 19 to hit (first roll was highest, if there is no advantage)
damage: 7 magic slashing

Attack 2: 27 to hit (first roll 12 to hit, if there's no advantage)
damage: 6 magic slashing

BA: almost as an afterthought, Grugga whistles Zap to his side.

Zap reaction: Zap will give disadvantage to an attack that would hit, if Zap is adjacent to the attacking target and Grugga.

Grugga has unwisely committed both hands to his weapon and can't cast shield right now.

While the demonic bird is occupied with Leelan, Aubrey makes a tactical retreat before using the powers of his talisman to unleash another two golden beams of eldritch crackling force against the hexed Vrock.

Move 10 feet to the south and blast the hexed Vrock 4

Eldritch Blast: 17 Force: 10 Necrotic: 3
Eldritch Blast: 9 Force: 12 Necrotic: 3

(If any of the blasts hits Vrock 4, Aubrey uses his maddening Hex to cause 4 more psychic damage to it)
(I assume the Vrock has spent it's reaction on Leelen.)