Playing a card this way follows all the normal timing rules for that card. For example, if you play a land this way, you may do so only during your main phase while the stack is empty and only if you havem't yet played a land (unless another effect allows you to play additional lands).

Once Share the Spoils leaves the battlefield, players may no longer play the exiled cards. If Share the Spoils is destroyed and somehow returns to the battlefield, it's a new object with no memory of the previously exiled cards.

Once a player plays a land or casts a spell from among the exiled cards, they can't play any more of those cards that turn. That is, it's one land or one spell, not one of each.

If you control an opponent's Share the Spoils and that player loses the game, Share the Spoils leaves the game with them and the first ability won't trigger.