Anyway of knowing what Online Versus maps you have completed? I could of sworn I went through the rotation with both sides but I guess not since the last Achievement didn't unlock.

No. Well at least not that i know of.

I think the problem is it doesn't count unless you play from the start or a certain time.
I'm pretty sure I've completed them all in Multiplayer, but a lot of them were me getting like >4 in, then instantly winning without doing anything.

It just pisses me off they haven't confirmed if you need a full room, what time can you come in for it to count,etc.

I entered a game right as in said missoin sucessful and i got the completion for it.