Wait! We had a guy who could turn people into chocolate and we didn't keep that as an NPC? Damn it, guys! We need to keep on top of this! Think of the conflicts that could have been avoided by chocolate-man!

Anyhow, I digress. In answer to your questions, Bastion, Metahumans make up about 0.5% of the population or around that number. They're spread out though so their population density isn't overly high. Exceptions are big cities like LA, New York or Washington.

Yes, powers are completely heretical. As I mentioned in the OP, the government were involved in something called Project Genesis in which they tried to breed Metahuman super-soldiers using two powerful metas.

That power you proposed actually sounds really cool! I imagine such a character would be valuable to any side!