I've been wondering about this too. I did some reading back and it looks like the source for Nathan is his Facebook page, as posted in 2019:
https://archive.md/C25Dz
His display name was Amy Nathan Petrelli (Lana Bartowski) - it appears to be Amy Maya Shaundi-Bartowski Petrelli now.
I recall him explaining on one of his suspended Twitter accounts that he named himself Amy Shaundi Petrelli after three fictional characters from tv shows/computer games.
Nathan Petrelli is a character in the tv series Heroes (of which 'Amy' has a tattoo). Bartowski must be from Chuck, another show on his favorites list. I guess it's safe to assume that Nathan was never his real name, just another character name to hide behind. So yes, I think
this user has a plausible story claiming his real name is Aaron Tidd.
I don't know about the others, but this one's got Ehlers-Danlos syndrome.