I would suggest you visit with the teacher about what kinds of music she chooses and how she lets the girls dress...our girls hip hop teacher does not allow anything more than Disney type music, stuff you'd hear on the Disney radio channel.
The girls were working on a routine to music by Selena Gomez last spring. They were tight fitting shirts under their hoodies, soffe football capri's and their hip hop split sole sneakers. They take the hoodies off so the teacher can see their abdomen muscles working while they are going through their warm ups.
She was on a couple of Broadway musical tours with Disney and she is a wonderful Christian person. I trust her to do tasteful actions and to not allow ANY unbecoming actions.
If you do not know these teachers then tell them you want to see them do a class or two before deciding.
Ballet will most likely get her more scholarship offers to college but she may like the rhythm of hip hop better.
If she wants to take both drop something else. I would keep the musical instrument because I was a band kid and loved every minute of it. I also loved every minute of choir. If she's in school she gets her instrument lessons free through school. During band class. That would be the cheapest way to go and then she can do two dance classes that should be affordable.
If she decides she hates one and loves the other then visit the idea of dropping one of them. I think if it's a recital year she should see them through to the end of recital but that would be up to you.
Every person who graduates from high school in our studio that applies for a dance scholarship to college gets a free ride, all bills paid full scholarship. They get them for ballet and other styles too. She will need to eventually take jazz, hip hop, ballet, tap, etc...she should be able to teach the younger girls when she is old enough to be an assistant teacher.
When the current teacher is out the assistant teaches the class. She is 14 years old and is very good with the girls. She is one of the best dancers in the studio. She works 3 hours per week helping the owner teach the little kids ages 3 and 4. Then she helps out in hip hop each class. She takes them through their warm ups and starts them working on their routines. The teacher is usually there and working on some new combination or ordering supplies. She is observing the class but the teachers assistant is working too. She earns the money for her own classes at this point.
Working as a teachers assistant is a great way to learn teaching skills and to pay her own way through the classes she wants to take. She can also earn enough money to pay for costumes, class outfits, and maybe even have a little bit left over if she works hard enough and will be there whenever she's needed.
Just a thought. Unless she's on the traveling competition team for her sport or is able to compete on a high level on her instrument I would focus on the one thing that could possibly pay her way through college.