First of all, congrats on losing all that weight, good for you dude!
As far as your questions go:
1. Don't wait to get to target weight before starting weight training, the scale is a valuable tool, but not as important as the mirror, ie. how you look is more important than how much you weigh.
2. Muscle burns more calories than fat so by adding muscle, you will naturally speed up your metabolism and burn more fat.
3. If you're just starting out and haven't really lifted before + your goal is to lean up, then it really isn't necessary for you to spend money on creatine or any other supplement (other than meal replacements/protein powder-but I really think of that stuff more as food vs. a supplement).
4. If you're diabetic, you should talk to your doc about what you want to do and get his/her opinion on any supps you want to take. Try and find a doc that's into working out though so you get a more "enlightened" opinioon.
5. As far as low sugar protein powders etc, you're best bet is to go to a supplement store like GNC or Vitamin Shoppe and just read the back of a bunch of products or shop online and educate yourself. Everyone here has their favorites but in the end you'll need to try different stuff and see what you like. I'll push my fav first

: check out the Isopure protein powder and drinks.