The last one is hard to implement, simply because it affects the genuine interest of chess.com to get a refund (there are many members saying that they pay a membership just for the auto-vacation mode, then if all the members have it they wouldn't buy the membership and this is a lost of money).
One way to solve the problem, premium members could have the option to turn on/off this option. If they put the option "on", automatically give the same ability to all his opponents, it doesn't matter if the opponent is premium or not. Thereofe, the user that need it, have it, and his opponent is in equal conditions against him, but this opponent wouldn't have this ability against others if he isn't a premium member too. If he want it, he has to pay a membership.
3) no more than 15 or 30 days in a row
4) auto vacation for all membership levels