You will be able to enter the MK for
MVMCP using your MagicBand
if you have your MVMCP tickets connected to your MyDisneyExperience account.
(You'll know it, if you can "see" your MVMCP tickets in your
MDE account.)
However, nothing is actually "loaded into" your MagicBand.
There is no reservation info, or ticket info, or credit card info, or FP+ info "put onto" a MagicBand.
A MagicBand just contains (and weakly "transmits") a unique serial number that is used to access the information that is stored in your MyDisneyExperience computer file.
The MagicBand works like the combination to a locked safe, or a key to a locked door.
The MB, itself, is not the file of info or the container of the info.
The MB just
unlocks the file of info, allowing it to be accessed from your MDE account when needed.