Choir sees the man trying to remove the helmet, and suspects that the object has somehow been cursed, or t any rate, is too powerful for the man trying to wear it.  She wonders if this is the duke they are looking for.

If possible, she will try to approach the man and cast Remove Curse.

Polly rush over together with Choir to the man. While Choir try to remove the curse Polly will try to reason with the man.

”hey there! Are you the duke? We have come to help, what happened here?” 

if Choirs remove curse fail she will try the  dispel magic spell

The man did not react to anything - his mind is obviously is not here. The words he is saying sounded as if he was arguing or word-fighting with himself, even his voice changes when he talks Celestial or Abyssal.

Meanwhile the portal flashed brightly and in stepped (or better say - appeared) three massive hairy horned figures with heavy axes in their hands. If before you had to deal with the skeletons, now you have the "pleasure" to see Minotaurs as they are, in all their glory - massive ferocious stinky glory. Blood-red eyes focused on the party.

Roll Initiative!

(M1 12  M2 8  M3 9 Lulu 6)

(Amazing! All I did is added the picture. There is no warning about dice manipulation - yet, the initiative rolls all changed! Never edit your post with a roll if you can help it)

Adray initiative 13 + 4

Choir initiative: 4

Fran was wary as soon as the two moved in to assist the man, though she couldn’t blame them. She too wanted to help, so support them she did. The artificer would remain on alert.

Initiative: 21

 (On her turn)

The battle smith will crack her neck to either side, roll her shoulders and then audibly crack her knuckles. Fran will reach into a pouch to grab a handful of powder to dust her hands off, and one could swear, she’d grow in size.

Enlarge/Reduce on herself.

She’d move in to a Minotaur along with Adray and Ordrag. The artificer will whistle for Brutus to swing around and join a target once everyone was in place. 

Ordrag Initiative: 3

(Ordrag should be near the portal with an attack readied, unless the minotaurs appeared as we entered. If he gets an attack as a reaction then... Attack#1: 17 Damage: 7 slashing. Otherwise, all good.)

Now this is a fight! Ordrag once fought off a minotaur buccaneer during a boarding and barely managed. Now there are three, but he's a far superior fighter than he was then. He leaps into the middle of the fight, facing M2 head-on and going hammer-and-tongs with his hammer and sword.

Action: Attack/Longsword.
Attack#1: 26 Damage: 14 slashing.
Attack#2: 21 Damage: 12 slashing.

Bonus Action: TWF/Warhammer.
Attack: 16 Damage: 13 bludgeoning.

Initiative: 25

when the Minotaur come out of the gate Polly grabs her wand and point it at the closest one. From the top a greenish bubble form and the shoot out towards it.

Melf’s acid arrow at level 3 for Attack: 10 Damage: 11 (or half damage if she misses.) 

The acid will stick to the Minotaurs hide and deal another 7 If it get hit. 

free action: “what did you do to this man!”

Initiative order: Fran Brutus Polly Adray Ordrag M2 Lulu Choir M1 M3

Fran, growing as she walked, run to a dangerous spot in front of the monster, his eyes following her move, teeth barred - the look of a predator ready to kill his prey and devour it. Brutus's paws were clicking in other direction, he came to a position.

Polly made the beast to turn it's head, not so much with her magic (though it definitely hurt) but with words. Minotaur did not answer (probably did not understand a word either), but Polly was noticed.

Ordrag, meanwhile, unleashed the steal barrage on the middle bull - to his delight, as he could tell, despite the serious wounds his sword left on Minotaur's body.

Adray - your turn!

Map:

Adray moves forward intent on hostility.  He plants himself between two of the beasts and readies his attacks.  "The bigger they are, the harder they fall," he grunts out as he takes multiple strikes against the creatures knees.

Move: move up to M1 next to Ordrag.  

Attacks: 1 normal and 1 bonus attack against each.  Bonus attack, if it hits will require a dex 14 save or they fall prone

Attack vs M1: 13 Damage: 6

Attack vs M2: 16 Damage: 6

bonus Attack vs M1: 23 Damage: 9 if hit he needs dex save 14 or be prone

bonus Attack vs M2: 11 Damage: 7 if hit he needs dex save 14 or be prone

M2 Dex: 13

M1 soaked the damage from Adray without a sound, but M2 dropped down. Not for long, though - he stood up and swung his axe at Adray: 

M2 vs Adray: Attack: 21 Damage: 12

(Shield or taking damage? )

Choir's turn!

(If Ordrag goes between Adray and M2, then M2 was prone for Ordrag's attack and Ordrag gets advantage, no? If so, here is advantage roll for Warhammer: 19)

(True - Warhammer hit as well!)

Choir hesitates, debating between trying to pull the helmet off the ranting man's head, or fighting the minotaurs.  In the end, she decides the monsters take priority, and steps up to Minotaur 3. giving him a whack with her mace (saving her spells for demons and devils) and hoping she won't regret her choice.

Attack: 27 Damage: 9

That was probably a wise decision - M3 looked as if he was about to charge into Polly or whoever will be on his way. Now, lacking the place for maneuver, he roared and plunged his axe on Choir's head - or tried to do so.

Though, not before Lulu used her deafening trumpet: radiant damage 27  Saves: M1 9  M2 4  M3 9 When radiant light settled down, the effect appeared to be devastating. The bulls were still standing, but burned more sevear than any flame could burn them. Yet, M3 attacked closer opponent: 

M3 vs Choir: Attack: 12 Damage: 13

M1 ignored Brutus, quietly standing at his site and attacked Adray: Attack: 26 Damage: 32

M1 simply missed, but M3's axe slid from Choir's steel armour. 

Round 2

Fran, Brutus, Polly, Adray (confirm shield!), Ordrag

Current map:

Don’t forget that the acid will deal an other 6dmg at m3 at the end if it’s turn. 

Polly yell at the bull in abyssal “tell me what you did!” Then the sound of a dolorous bell chime in the hall as Polly cast toll the dead on M3.

Wisdom save 15 or take  6. 

well that was 2 useless d12’s... 

Arming herself with righty Tighty and lefty Lucy, Fran will try a stab at enlarged melee combat (M3).

Attack 1: 22 Damage: 6 + 1
Attack 2: 21 Damage: 4 + 2
BA: 24 Damage: 7 + 4

Brutus will hold his position on M1 to provide disadvantage against Adray.

Adray confirms shield, 12 is a lot of damage.

"They are teetering, make them fall!" Adray yelled out and took much the same tactic as before.  He redoubled his efforts focusing on their knees.

Attacks: 1 normal and 1 bonus attack against each.  Bonus attack, if it hits will require a dex 14 save or they fall prone

Attack vs M1: 18 Damage: 10

Attack vs M2: 10 Damage: 10

bonus Attack vs M1: 17 Damage: 10 if hit he needs dex save 14 or be prone

bonus Attack vs M2: 19 Damage: 9 if hit he needs dex save 14 or be prone

Puffing a bit with the exertion of battle, Ordrag nonetheless calls out to Polly: Maybe him too close to portal. Need to get him away.

Continuing to attack M2, plus use Action Surge to attack again.

Action: Attack/Longsword.
Attack#1: 13 Damage: 13 slashing.
Attack#2: 28 Damage: 17 slashing.

Bonus Action: TWF/Warhammer.
Attack: 24 Damage: 10 bludgeoning.

Action Surge: Attack/Longsword. 
Attack#1: 25 Damage: 10 slashing.
Attack#2: 22 Damage: 12 slashing.

----------------------------

Should have made advantage rolls for the longsword in Round 1 as well, just in case I get a crit: 25,24

And here's some advantage rolls just in case M2 goes prone in Round 2. 
Longsword: 28, 29. Warhammer: 16. Longsword: 28,18