The kings would most likely get killed for new vegas by another faction,10mm pistols cant save their lifes if NCR or Cl deside they want the place.
Well, on the assumption you decide to make the Kings the new and powerful fourth family. NCR and Caesars Legion would be to busy licking their wounds and biding their time, and if you gave them access to the Securitron Army, Vegas would be a safe haven.
Well the thing with House is that his idea is to bring back technological expansion, and I think it's a matter of faith and opinion. Honestly, I just have a feeling that House, despite his cold and distant personality, is the best hope for humanity.