I hope Sergio gets the drive, he deserves it. I just hope he doesn't end up what Irvine / Barrichello / Massa have all been before him...... 
No one deserves to sit in the 2nd car at Ferrari!
No. Perez certainly has more potential that that.
I think Ferrari will stick with Felipe for this year, but with a few more bad races we might see Felipe retire - he can't be getting any joy out of what he doing ATM. If he did, I think SF will put a "stand in" driver in the car, most likely they will look to Jules Bianchi. But, here's the big thought from me on this, I definitely see LCdM pulling out the big cheque book and making a beeline for Seb.
As for the race, I was super impressed with the improvement Ferrari got out of the F2012 with almost no new parts in Malaysia. For China there is a swag of new parts, so, if they can continue the improvement they might just be a little closer to the pointy end of the 2012 performance stick.