1. That is a bad choice if you are going with only two or three suits. If you had 3 or 4 already, I could see adding it.
2. Yes. Start with one black and one brown, but I would add a couple pairs in the near term. Don't forget shoe trees!
3. That is fine, but they should both be solid. You may be better off going one navy and one charcoal. Wear the brown shoes with navy and black with charcoal.
4. Do at least one white shirt.
5. Yes, but you seem to be on a tight...