One of my recent concerns (feel free to add this to your question list, ddrongowski!) is how difficult it will be to temporarily link, and then de-link, accounts. (Profiles? I don't quite have the lingo down yet.)
For instance, if you run into someone you know while in the parks, can one person reserve, via smartphone or otherwise, Fastpasses for both? Do your accounts have to be linked to do so? (My interpretation of their literature is 'yes,' otherwise people will be reserving numbers of FPs far above their needs.) Currently, one person takes all of the group's KTTW cards and does a FP run. What would the MM+ equivalent be? Or would you have to stand around on your phones, crossing your fingers that you get the exact same FP window at the same time?
Ditto for the reverse--if you're linked with people but want to get FP+ for a different park, can your profile go solo? Example: family of four, Mom does all of the account setup and planning, but the day before the trip, 16-year-old son says he wants to do DHS on a day when the family is going to MK. Can Mom cancel one of the family's four FP+ profiles for the day (without having to cancel the entire FP+ reservation) and re-reserve Son for [whatever is still available at] DHS? Would Son have to log in and do it himself? If he prefers to do so, could Son do it himself, or would Mom have to do everything, since she signed up as the family's 'lead' profile?
(I'm sure a lot of these will become clearer once the program officially starts and picks up speed. If anyone can shed a little light, I'd greatly appreciate it!)