Who to start? choose 2 running backs, 2 wide receivers, and 1 more of either?

If I were you I would start Kolby, MJD and Chatman (That is if he's not still injured. As far as the wide outs go you are lucky to have both edwards and moss. I would definitely go with them. I wouldn't start holt in place of a rb because you never know what could happen with st. louis.