Would a small backpack that isnt clear or see through be okay to bring?

Yep. My wife had one and it was fine. We went in and out (backstage passes).

Yes you can, like others said, they do bag checks when you enter, as long as you pass that, you're good to go

They do bag checks upon entry but not sure if backpacks are allowed ... I wouldn't chance it

They checked us going in and had metal detectors. Not sure about backpacks but my wife had a purse.