It's highly stage dependent as to which Pokemon does the best of the 3.
I'm also bad at playing good players who play rather uncommon characters I play against, but with people who don't play them very well. I tend to run into stuff, which is why you were about to 3 stock me game 1, and then I almost won. XD Like everytime I play Bored's Ike, he takes DUMP on me game 1, and then I remember how to play against a good Ike, and we have close games 2 and 3.
Against PT the strategy's what's tricky, since it's 3 characters, and I play differently against all 3 of them, and differently from that on different stages depending on how many platforms there are.
A +2 is a MU that almost always has the upper hand. Snake and Falco will always have solid ways to gay Bowser, for example.