A:AnswerYou can only redeem a code once. If you are logged in to another device with your account, you will have access to it (As long as Sony keeps it on their storefront) but you cannot redeem the code on another device once it is used.
A:AnswerYes it will require PS Plus or Xbox Gamepass. Both systems require memberships to play online. There is also rumors that Rockstar might require a GTA+ account.