Yes, although the Swan and Dolhpin are not WDW operated resorts, they will transfer your luggage to a WDW resort (such as BLT). Just ask bell services at the Dolphin for assistance. The luggage may not arrive at BLT until late afternoon, however, and you will need to be present in your room to have it delivered, so, if you need items during the day, you should pack a day bag. The alternative is to take a cab over to BLT with your bags and have bell services hold them for you there until your room is ready. This may be difficult if you need car seats for your children, however. An alternative may be to send one adult in the cab to BLT with the luggage while the other adult takes the children to wherever it is you have chosen to spend the day and then meet up after the luggage is dropped off.