[makavel]

#1 You can set individual ring tones per contact for calls, but I don't think it's possible for text messages
#2 If you're asking whether you can have the ringtone for text messages silenced while continuing to have other ringtones work, the answer is yes. You can control all of the text message notifications (ringing, vibrating etc) completely separately from incoming calls.
#3 I'm not sure about this, but I think you can continue to make themes if you'd like. I know you can disable TouchFlo3D and go back to the standard Windows Mobile interface, meaning that you should be able to make themes for it. Someone with more knowledge on the subject can hopefully answer your question better.

As for the screen resolution issue, I think that most software is available in the VGA format as well as QVGA, so most of the software you use should be available (or might even work in the form you have it). It seems like a lot of software just scales from QVGA to VGA if it doesn't intrinsically support VGA.

I hope this helps! Good luck!