Will security let me go down to the lower level seating during pregame warm ups to try and get some autographs or will they check my ticket?

Early on you can

Get there early (as soon as possible) and they will let you go down to the first row. Just check in with the usher.

Probably not but it wont hurt to ask

Security checks your ticket to get to the lower level of the stadium

They were checking tickets last time we went, so I dont think you can do that.