What about the cutiemark?

Maybe:

AB's: An 사과, 애플 covered with a 꽃 bloom
Scootaloo's: A scooter
SB's: A 음악 note

I think 사과, 애플 Bloom's would have something to do with building things, so maybe something like a hammer and nails. Scootaloo would have either a scooter 또는 a flaming wheel, and Sweety 벨 something musical, like notes on a staff. Just in my opinion :)

Let's see here...

사과, 애플 Bloom will have a cutie mark that looks like a flowering 사과, 애플 seed(Apple... Bloom. How hard can that be to 디자인 a cutie mark around that name?).
Scootaloo will most likely get a cutie mark that looks like a scooter, only because she's awesome performing stunts with it(at least, in my mind).
Sweetie Belle will have a microphone for a cutie mark. I wonder if any bands have an opening for a female vocalist. That would be the best way to get that cutie mark, in my eyes. Buck stage fright; when 당신 have your cutie mark, all fears go out the window.

Applebloom: Something that has to do with art
Scootaloo: Something aero dynamic
Sweetiebelle: A microphone

사과, 애플 bloom:a basket full of apples
sweety belle:music notes
scotaloo:a scooter