You are definitely starting Morris and Rice because of the matchups. I'd probably start Lynch but there is a very good case for starting Charles as well since he's playing IND and should have a field day but he has more downside if the Cheifs fall behind. I think I'd go with Lynch though because he's safer and you have some really good RBs already so you don't need as much upside from him.
I go with the Houston Defense. It's just a very favorable matchup. SF has a good offense with Kaepernick and Gore so it's best to bet on Houston getting interceptions and turnovers on Ponder and that AP only gets 1 touchdown.