First of all I have to say that this is a unique essay, and one that certainly captures the reader's attention. So well done!
Do you think the AO's will know who/what Mulan is?
Doesn't matter. They want to know you, not Mulan. In case they are looking for additional animation-character-trivia knowledge, they can always google.
I wanted to use "detailed" bullet points since that's what field reports are like, but I didn't think the AO's would like that. What do you think?
It's fine as it is. No need to change it.
If you're wondering why I chose to use a field report, it's because I was watching a movie and I thought the idea was interesting. I'm not planning on majoring in anything that has to do with field studies though so is that bad?
I think it's brilliant. Just out of curiosity -- what is your intended major?
I think in the field report, I switch back and forth from a silly tone and a more professional tone. Would it be bad to go with the silly tone?
I don't think there should be any problem with that. However, I do think your essay highlights your superficial traits like appearance, physical behaviour, etc. more than your character. A roommate would want to know what your likes and dislikes are, whether you are an extrovert or an introvert. Basically, stuff that projects your personality.
These habits
occur multiple ...