From customer service:
“We appreciate you taking the time to allow us to assist you. We are sorry to see you have linked a MagicBand to the wrong person in your party.
Regrettably, MagicBands may not be linked to another person once they are linked. This is a security feature to help protect the members of your party.
However, for any technical support for MagicBands, we would like to refer you to the technical support team for My Disney Experience.”
That is why a lot of people won’t buy MBs off of eBay.
You cannot transfer magic bands. I called and asked for a recent trip when I couldn’t find DH’s. I had to buy him a new one even though DD and me had two and one neither of us had ever used but was attached to a hotel reservation. Now if you buy them outside of your hotel reservation they are not assigned and you can assign them but once you’ve done that you can never reassign them. So this means for a hotel room key or to charge around sure someone can wear yours but you cannot use it as a park ticket.
We had rented points for a treehouse and last minute our boys joined us. There was plenty of room in the treehouse but we didn’t add the boys onto the reservation since we had rented points (and actually my DSIL did it so I couldn’t add them) so they used some of our duplicates as room keys/gate keys as we drove and their own bands as park tickets/fastpasses.
I’ve had MB reassigned from a reservation b/c DS didn’t like the one I ordered for him so DH said he’d swtich.
I’m sure y’all will figure this out 
TTFN
If you don’t have everyone in your party listed on the room reservation, they can’t use Magical Express or access extra magic hours. I’m not sure why you wouldn’t have everyone who is staying in the room listed on the reservation.
The plan is to add everyone once we I am certain which days and location we are keeping. So, for certain by a month-ish before we arrive. I just don’t want a CM to give me an over-the-phone side eye for having two overlapping really long reservations. Basically we are staying two weeks, and I’ll want a leading leading reservation on top of that. I wanted DH to have the leading reservation.
I had a leading reservation that overlapped on top of a split stay renting DVC points for 3 nights followed by 2 nights at a value. All three were in my name.
At one point I spent an entire morning on the phone between dining and the IT help desk trying to figure out why I couldn’t book some ADRs that should have been available…not one person questioned my overlapping reservations.
I would add who you need and order your bands.
Will do.
I tend to worry.
There is no need to actually request MBs for each member of the party on the reservation right away. You can hold off. So, go ahead and add everyone to the party for each leg of the stay, but just don’t order the MBs. Once you finalize things, you can then decide which person wants what MB. And, of course, there is no need to even request a MB if you don’t want to. Because we were doing a split stay, PLUS I had an AP, there was a point where I didn’t bother requesting a MB even though I could have gotten another one simply because there just wasn’t a need for another one.
Well, this will be our first and only trip. Being extremely frugal, my brilliant plan was to get one MB for daughter and DH and I using the cards. My reasoning was that I wanted one MB because I want the ride photos that look for MB’s to see a MB. But for DH and I, parks, parking lots and room entry was all we’d need.
Then when DD and I were shopping for her MB, DH overheard and said he wanted one too. So, now we are getting a MB. You guys are right. I’ll add them to the day we are most certain to keep.