Of course they could, there were (and still could be) Mods who weren't who they said they were. Using fake photo's and making up fake life stories. GaG doesn't seem to mind so I find it perfectly believable that Admins could be too.
I suppose they could be. But it's unlikely since they most likely take this website seriously - as they should. They'll never know when an opportunity may arise that would be better than managing this site. Who knows? Maybe they'll keep managing it, even if they get that opportunity.
Potentially I guess. Having a fake picture up isn't really catfishing, it's more attempting the whole persona behind it and generally trying to pursue some form of relationship. In that sense, it's pretty unlikely lol.