Can't see anything you forgot.
Head space is set by the barrel maker and I'm sure there's a barrel and bolt out there that doesn't match up but I've yet to see one or even know anyone who has seen it. If you want to check to be sure, buy a Field gauge from Brownells for less than $25.
One piece cantilever mounts are pretty easy.
Scoped you'll be in the 8lb range.
Stake the castle nut on the receiver extension, don't go crazy when tightening the flash hider, less torque means less stress, same with the barrel nut 40-50' pounds is where I try to stay, buy plenty of magazines and have fun.
