It's hard to say who's even gonna play. Super/Vampire has been doing so well I think we will see him as ace and DRG could very likely not appear. Tails the super-sniper will also probably show up given his exceptional performance last time they met here. Keen will probably be saved to deal with Squirtle if he comes out since he looked like he had the better of him when they met in code S.
On IM's side they look like they are taking GSTL seriously for once so I think we'll see Squirtle 3rd again no matter what, and even though Yoda is playing in GSL, I think he'll be ace, since he looks like IM's best player right now.
I can't tell who'll win the first match, I think First has a slight advantage, but I think whoever wins the first match will probably take the series 4-3.