If there arent VIP tickets on offer, you should be able to get in to the lounge/bar area with your GA ticket, and yhere are sests there, too. If they offered VIP, though, thats not an option, though.
I was seeing Robert Plant there a few weeks ago, they would let you come down to the lower landing, but no further. They only let me stand there for two songs, then back up the stairs to my seat. Security was very tight that night.
It depends on how full the show is, but i am certain you could trade someone if you felt like you had to sit down.
Depends on how sold out the show is. If it is totally sold out then probably not. If it is not sold out then you can probably sit in the mezzanine or balcony, just not the loge since that tends to always sell out. You can always ask an usher and they will tell you if anything is available or not.
Thanks! Your answer is awaiting moderation.