Feb 28, 2016
So I was wondering: if I grant cards flashback via Past in Flames (or a card has flashback normally) can I discard cards to cast them from my graveyard via Dream Halls' effect? Thanks :)
No.
You can only pay one alternate cost to cast a card, and the only option you have to cast those cards from your graveyard is to pay their flashback costs.
If you were given permission to cast the spell through an effect that doesn’t specify flashback, like Yawgmoth’s Will, then you could discard cards to cast them with Dream Halls.
