Ticket and fastpass are not attached to the Magicband.
The ticket, the fastpasses and the Magic band are assigned to a person.
Let's say I make the
DVC reservation. I go into my My Disney Experience account and enter the DVC reservation number.
Let's say the people going with me have never gone to WDW before. I create identities for them in my
MDE account. So I create an identity for John Boy. I create an identity for Jim Bob.
I buy tickets. If I buy them online from Disney, the tickets will automatically appear in my MDE account. If I buy them from a different vendor, I add the ticket info to my MDE account.
Once the tickets are in my MDE account, I assign one to John Boy and one to Jim Bob.
I use my MDE account to customize Magic Bands for each of us. Each person's Magic Band is assigned to the appropriate person in my MDE account.
If John Boy decides not to come at the last minute, I can reassign his ticket to someone else in my MDE account. I can throw out his Magic Band.
If Erin decides to take John Boy's place: I think I can call and add her to the resie, create an identity for her in my MDE account, get fastpasses for her, customize a Magic Band for her if there is time. If it is very last minute she can gets magic band at the hotel. Can she take over John Boy's hotel spot and fastpasses and use his magic band? Maybe. I don't think everybody needs to show ID at the front desk.
But if I die before the trip... it has all been set up in my MDE account. Can Jim Bob become the lead name on the resie? If David's and the DVC owner agree to do it, doesn't that mean Jim Bob needs to enter the resie into his MDE account? Would he have to create an identity for everyone, re-customize magic bands? Wouldn't the fastpasses be lost?