Dire Flail // Dire Blunderbuss

If the equipped creature isn't on the battlefield as the reflexive triggered ability granted by Dire Blunderbuss resolves but it had lifelink when it left the battlefield, you will gain life.

If a card that isn't a transforming double-faced card becomes a copy of a card with craft, it'll stay in exile if you activate the craft ability. It won't return to the battlefield.

The back faces of some cards with craft refer to cards "used to craft" it. This refers to the cards exiled as part of the cost of the craft ability of the front face. Those cards are considered to be "used to craft" that permanent as long as they remain exiled and the permanent remains on the battlefield, even if the permanent's controller changes or some of its characteristics change (because of a copy effect, for example.)