I don't think Orange County is going to hold for too much longer for Republicans. It's a matter of when it actually falls.
I doubt it. Obama lost ground with whites (and with Hispanics, believe it or not) in OC, and the swing was only small because of the massive swing with Vietnamese-Americans that probably had to do with a pro-incumbent culture plus the "self-deportation" crap.
Whites matter less every election. And how much more ground can he lose with them out there? They've been heavily GOP forever. And everything is relative to the national election. A Democrat would certainly win in a national landslide.