Evade and Counter isn't a character specific equipment.

Auron is ineffective against Nimble and Aerial opponent. (I remember switching for Wakka when I fight those monsters.) Also, who says that Dante will close in and attack? He can stand back and shoot, charging up his Devil gauge, and wait for Auron to act.

If Dante goes into Devil Trigger with Alastor, he can (Air Hike, and then) use Air Raid and shoot lightning down from the air, it is a ranged attack.

The once in a hundred isn't a good argument, because you won't have that many chances. You are assuming that Auron will dodge every attack from Dante, which is not going to happen.

As for Overdrive, you will need to charge up the meter. In Auron case, he will need to deal damage to Dante in order to charge up the meter, or taking damage. (Unless you include the turn reaches Auron when he's the only member in the party who's able to fight...) In this match, I don't think Auron will be able to use his Overdrive more than once.

So what if Auron uses his Overdrive? He needs to execute it really fast so that the overdrive will be at its maximum effect. At the same time, he needs to make sure it will actually hit Dante. (For the case in Tornado, maybe not.) But then Dante can throw in a Holy Water and break the move. (Holy water destroys all the enemies in the area. Against bosses, it will interrupt their moves and damages them. Quite a lot of damage, too.)