I can see Fujie Reina cranking out tons of merchandise and IVs. Which is what she's sorta doing now.
Yuko has the highest chance of surviving outside of AKB as a talent of some sort. She knows how to play the game, and she plays it well. Takamina is promising too, she's been on a lot of TV shows, and it's been shown that she can speak for the camera well. And she has that 'cries anytime anywhere' factor going for her, too. Lol.
As for soloists, I think Yuka would be able to make it as a solo singer, although I'm not sure in what capacity. I think it's mostly because of I haven't seen much of her personality-wise, at all.