I would very much enjoy seeing her in Ep3... and it's not too much of a stretch. She's got qualities the G-man would certainly want to put to use (insane tenacity, great thinking skills, physical endurance has to be amazing- after all, for Portal/Portal 2 to succeed, she'd have to do everything on the first or second go), so she could be a huge boon for wiping out the Combine.
As for the silent protagonist thing, it's been confirmed that she is silent by choice. The robots in Aperture piss her off, so she doesn't talk to them, I'm sure she'd have something to say if/when she found humans.