I am a tour director for a company that creates trips for high school music groups. I am in the parks with bands, choirs, and orchestras 8-12 times per year. I love my job!
To answer your specific questions...
1. When they kids receive their ticket info is up to the travel company they are using, or their directors, if the group is planning the trip on their own. What our company does is email the group their ticket confirmation numbers at just more than 30 days out, so that they can link the number to MDE to be able to book fastpasses. We do not give the kids their actual ticket card until arrival morning, but they don't need those to book FP, just the number from the back. Even if your daughter does not receive the ticket information before arrival, she can still link the ticket to MDE as soon as she receives it, and can book FP in the app. No need to visit a kiosk.
2. As a PP mentioned, the kids generally tour the parks in friend groups, so that is how they book FP. They just have to be aware of the itinerary, so they know which park to book in, and what times would not conflict with other scheduled events.
3. Most marching bands perform before the Festival of Fantasy Parade in the Magic Kingdom. There are often 3 bands performing each afternoon, and the first one steps off about 2:30, on days the parade is at 3:00 (which it is, in February). However, at busy times of year, they also can march in the morning or evening. (They also could march at Epcot, before all the construction, but they will not be there for a couple years, at least, and maybe never, depending on how the "flow" through the middle of Future World shapes up with the construction.) Your child's director should know at this point the general performance details, and will receive exact timing about 3 weeks before the visit.
4. If the group DOES march before Festival of Fantasy, my favorite spot to recommend for parents to watch is the hub, about "4:00", if you consider the hub is a clock, facing the castle. This is because they will enter the hub from the Liberty Square bridge, and circle in front of the castle. The spot I mentioned is a wonderful place to see them and get some great pics with the castle in the background.
5. Many groups also do a Disney Performing Arts workshop in addition to the performance. That is up to the directors, and they would have that information now.
6. The group will have so much fun! They have to realize that their schedule is not their own, especially on workshop or performance days. But they still always manage to have a great time together.
7. Most groups receive either meal vouchers or dining gift cards to cover meals. We much prefer the dining cards, because they are so much more flexible.
Let me know if you have any other questions!