I think many scenarios can be done :
- 1 : Larcade, being the arrogant Zeleph's ultimate weapon made to fight Acnologia, should engage him first and then will one shot to death by a boring Acnologia. Then Acnologia should engage the Dragon Slayers like Kirin, Mardmole and Sting, while Dogramag should have fun with Erza and Jellal.
Even a toying Acnologia should destroy all combine three faster than Dogramag should destroy the lovers (Jellal can resist with his speed and Erza's stamina can fight longer). As only the four are winners here, then,there will be Acno, Dogramag, Erza and Jellal by default.
- 2 : Acnologia directly attacks Dogramag. All people around are fighting in different place. Larcade uses his axe to floor all people bar Erza who is not affected by pleasure magic and should strike him with enough speed and power to defeat him, with enchant if in need. I can see Jellal destroying Mardmole with AoE Attacks combine with his speed while Kirin crushes Sting before engaging Erza and Jellal in a battle at three (like the 3 girls in GmG). I can see Acnologia killing Dogramag before the end of their battle. The four winners should be Acnologia, Kirin, Erza and Jellal.
In all scenarios, Acnologia, Erza and Jellal are here. I should give them my vote. For the last one, I still don't know between Dogramag and Kirin. Waiting to see commentaries.