"New Pegas", yeah. I think there's like, half a dozen "New Vegas" crossovers, one of which is "New Pegasus", which is someone else. Mine was one of the first, and there's a reason it's spelled that way.
No, you probably don't want to know.
Generally... yeah. A lot of the draw to the fics is that they make plenty of lore references to both the game series and the show, and it rarely seems forced. Like the Hydra chem (in this case, made from actual hydras). Or this region being known as the Moojave, part of the greater San Palomino...