How do I combine those 2 on one cake????

Could you do a sheet cake stage with the actresses on top dressed in cheerleading outfits? If there aren't too many names to pipe, you could add a marquee saying something like "Little Women"
Starring: list all the cheerleaders names? For the rest of the kids list their names with tittles such as gopher, light boy, 1st boy, you know-all those crazy tittles they assign to people.

It's only for 1 girl and those are the activities she was involved in in school. I'm thinking comedy/tragedy masks and pom poms. Could work?

what about a fbct of a cheerleader with a comedy tragedy mask in her hand kinda like a masquerade mask?

How about High School Musical. My partner FatandHappy did one and it came out so cute.