We have the 10MB share everything plan. Is it possible to set a per line cap per phone (i.e. once one of the five lines hits 2GB cell data shuts off for the remainder of the month for that line) so as to avoid overages?
Yes, but you need to add the $4.99 FamilyBase option. This will allow you to give each line a limit, both total amount and hours of the day that access is possible.
Thanks. I assume that is a monthly charge?
Yes, monthly, first month free.