You roll your HP by hand or use invisiblecastle.com, your choice. I work on the honor system; if someone cheats, I'll probably find out in the long run because in my experience people who cheat don't usually do it just once or twice. That said, go ahead and roll HP yourself. I don't allow for re-rolling 1s on HP. If you don't like what you roll, then you can have what I roll for you (but if you take what I roll, that's it).
I'll have a look at the gambling spell from the Draconomicon. Maybe I can lift the evil tag on it.
You have definitely provided an IC justification for taking ranks in the skills you list, and I appreciate that. I wouldn't deny someone ranks in skills because they hadn't rped the acquisition, but I definitely enjoy (and will reward) it when players go to the bother of rping skill acquisition.
A 1st-level wizard gets all the cantrips. He also gets 3 + his Int bonus in 1st-level spells. At 2nd wizard level, the PC would get 2 new spells of any level he can cast. Voadam would therefore get 3 + his Int bonus in 1st-level spells; it doesn't matter that he's taking his first level in wizard at 2nd level overall. And, yes, scribing spells later on can be expensive.