I agree with the previous posters.
For bag transfer, either call your resort's bell services to have them pick up your bags, or bring them to the bell services stand, yourself. The earlier you can get your bags to bell services, the better the chance you'll have of getting them transferred earlier in the day. When arriving at your new resort, either stop at the new resort's bell stand, or call from the room to request the bags be delivered. As with any baggage handling, a tip is appropriate (on both ends).
The MagicBands are available with each resort stay. There is no cost, when ordered to go with your Disney resort stay, so many guests order new ones, for each stay - either to get a new color/design or to personalize as a remembrance. However, one MagicBand will (should) work at all of your resorts, park entrance, charging, etc., whether for your next trip or other future trips. You do not need a new band for each resort.