I have the MDE app on my phone. Haven't used it yet but will soon! 
I would like to add it to everyone in the group's phone for the purpose of the wait times and maps, but don't want anyone to accidentally cancel a FP for the rest of us
(2- 11 yo, 2- 16 yo, 2- other adults plus me)
How should I handle this? Should I create a separate log on for them?
Would they each have to have one or can multiple users be logged in at once?

I would like to add it to everyone in the group's phone for the purpose of the wait times and maps, but don't want anyone to accidentally cancel a FP for the rest of us

How should I handle this? Should I create a separate log on for them?
Would they each have to have one or can multiple users be logged in at once?