Yeah, default positions might work. Obviously, they could be occupied by other figures, too, but most figures have at least 2 potential starting positions, so it's likely that at least one is free. Plus you could just say that a valid starting position has to be free, otherwise you can't resurrect that figure.
And I think, the double-draw idea is a bit too OP. 😅
Even as demonstrated in the video, if you're allowed to play just 4 consecutive moves, you could easily checkmate without your opponent able to do anything...