They put any newly available tickets on sale at the points level at which it sold out. If your son didn’t previously have enough points then that will remain the case.
100% correct since the arrival of PL sell outs. There is though a trend for people to come on to NSC to claim the opposite in hope that one day it will happen.
Not sure it helps you much but we have never sat where we like at away games or not for many many years. Also no-one has ever been sitting where they like in our seats apart from once away at Bournemouth when we were 15 minutes late so it was fair enough.