Meitheisman wrote: If you go over 70 because of youth pulls do you have to fire/sell players when the season ends or can you maintain your team over 70 players for as long as you want?

As far as I can tell, you keep the players. There isn't any big changes involved in the off-season. Wages are still paid and friendlies are still played, the only normal changes made are the new schedules are added, and players get older and get raises. Nothing resets, so I see no reason why roster size would be required to be adjusted. I've not heard of anybody having to cut players during the off-season. Though, to be fair, I've also not heard confirmed reports of anybody keeping over 70 players during the off-season either.