Umm... reading the other responses is making my head swim.
The Hilton conversion will eat away at your miles-- you wouldn't get 3 award tickets.
Midwest Airlines won't work because while you can get an AA ticket SAP--LAX,
you can't do a stopover on an award.
You can plan your trip as you describe using your CO miles.... fly SAP--IAH--DFW on CO, then DFW--LAX on DL..... DFW is very much on the routing between SAP and LAX- and you will save time without the MIA transit.
Have you checked CO availability for your dates?? I'm guessing you already have.....