1. Depends on how shiny it is. The pictures give no hints whatsoever. Between that and ordering a suit online (e.g., too tight would look too casual and/or bad), it seems too risky.
2. Yes. Why start without black? What if there's a formal event soon that requires it?
3. Not ideal, but not a crime. This assumes there are some style differences between the two.
4. Bad idea. Any business wardrobe should include white dress shirts. Lack of variety might be interpreted as...