Donaire would have his way with Mares fairly easily. The guy is a beast and is on a different level than Mares.
That lead straight right, the overhand right, and the left hook counter seemed to catch Mares pretty easily and stunned him a couple times against Agbeko, Donaire would finish him.
Nonito is untouchable in this division due to his size advantage.. the only place where he gets a challenge is at 122 and 126.. just like when Oscar was at 130.. he's untouchable coz of his size advantage
Realistically, Mares cannot beat either Agbeko or Darchinyan. Sure, he can buy a meaningless victory over them, but he will never be as good as either. He may be in the top 5 of the division, he may not. But putting him in with Donaire would just be a mismatch. Even with Mares cheating just as blatantly as he does, the huge difference in ability will see Donaire KTFO Mares whenever he chooses to do so. Round 1, round 2, whatever - the second Donaire gets bored and decides that it is over, then it is over.