1) Some people like to; I didn't. I can't remember if there's any 'bloatware' pre-installed, but I'm pretty sure there isn't. Either way, you're used to Windows (by the sounds of it), this is a Mac.
I have tons of programs installed, I've also had tons of junk that I've downloaded, installed, and then removed, yet it's still as fast as when I bought it, which is something to which most Windows users can't relate, I imagine.
3) My macbook runs great on 2gb. It's very fast.
7) Not sure what you mean. Could you please explain.