Most of the sites will be about the same (Seatgeek, Stubhub, Ticketmaster). I'd probably wait until tomorrow since you'll have four teams who are going home selling their tickets.
Yeah they are faking those screen shots. I have had similar ones shared with me. Go with your gut. Probably a scammer if you can't verify them on here.
Nope. Never have. Sounds like BS.
I have encountered a few scammers already for the UGA game though. They have clearly found this forum. Be careful out there.