The TV in the living room has a DVD unit already connected. They also have external jacks for your own equipment. Those in the bedrooms most likely do have the external jacks as well, but occasionally (seldom) you'll find one that doesn't.
We just returned from OKW two weeks ago and I asked DH if he remembered hooking up DS's Xbox to the TV in the living room. He said that he had packed the adaptor and that without it, he could not have hooked up the Xbox.
Definitely yes to the living room TV, but I have no idea about the bedroom televisions ability to be hooked up to game systems. We did, however hook our portable DVD player up to the one in the master, so I'm guessing the answer is yes.