Re: Are regenerations still capped at 12?
We do have proof that lives can be extended. In "The Five Doctors", the Master (who by that point had already had 1-3 incarnations after his supposed final "natural" incarnation, depending on how you look at it) was offered another regeneration and a completely new life cycle by the high council. He accepted this as though it weren't a big deal.
I always just assumed that the council was basically BSing the Master. They may have promised him a new life cycle, but that doesn't mean they could have actually given him one. (And there's no real proof that the Master even believed them when they said that.)
It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shakes, the shakes become a warning. It is by caffeine alone I set my mind in motion.