8 Jun 2018
If you don't cast the exiled cards, they remain exiled. They can't be cast on later turns.
8 Jun 2018
Stolen Strategy doesn't change when you can cast the exiled card. For example, if you exile a sorcery card, you can cast it only during your main phase when the stack is empty.
8 Jun 2018
Casting an exiled card causes it to leave exile. You can't cast it multiple times.