Yes you can..
Chairs are best so that you can see better.
Yes and its recommended unless you want to sit on the grass.
Yes
Yes they will let you bring chairs it is an open-air Amphitheater with no seating
Don't have an answer for you, sorry.
I have seen people sitting in chairs near the river towards the back of the venue, but I am not sure if every concert would allow you to do so...this would be due to concert size and the capacity of the venue :)
Thanks! Your answer is awaiting moderation.