Presumably it won't be an entire group of 50-100 students all making the same FP+ reservations. If it's like my niece's band trip, you'd have the large group break up into smaller groups of 5-8 people.
In that case, the group can go to a kiosk, scan all of the tickets and then make FP+ choices for everyone together. A CM will be able to help them, if needed. I'd suggest they agree ahead of time what attractions they want to go for and then have an appointed "leader" be the one doing the work on the kiosk. (I have visions of 9 tween girls huddled around a kiosk all yelling "I want to go on Big Thunder!" "No, we should ride Haunted Mansion!")
If your daughter and her friends are tech savvy and she'll have a smartphone, she and her friends could all set up profiles on MyDisney Experience.com and link to each other as Friends. Once they get their tickets, they should probably be able to scan them and link them to their profiles. Then they would have access to making advance FP+ choices all together on the phone.
Alternately, if not everyone wants to/can set up their own profiles, someone could be the "leader" and set up "managed by them" profiles under their account, link all the tickets and handle the job of making all FP+ choices for the group.
If they can't link their tickets, then all they've done is wasted a little time setting up the profiles.
If they *can* link the tickets, then they'll be in a great position to make their lives much easier in the parks.
-Rob