Offsite guests (which technically you'd be at the Swan/Dolphin) will likely be offered the option to buy Magic Bands to use for their tickets. But you can't charge back to the room and you can't ship any purchases back to the room from there.
If your BW stay comes first and Magic Band has been rolled out (which it likely will be by April), then you can continue to use the Magic Band you will be issued at BW as your ticket.
I will say that my vote would be to stay put at BW for all seven nights. It's kind of a hassle to pack up and move for two nights.