@Octo
Alrighty, I'll go ahead and hand down my verdict.
Now, the thing is that skills aren't actually that impactful. Their main purpose here is to serve as a way of codifying a character's theme. This isn't the sort of environment where most skills will have much weight outside of guiding character interaction.
With that said, to reach even decent experience in three styles of martial arts is near-impossible order by the age of fifteen, if we're talking true experience and not the waterdown kind. Also, just from a posting perspective it's troublesome for you should she ever make use of that talent, because it requires that you've done a decent amount of research on all three styles, and have a good enough grasp on all of them conceptually that you can think of how to blend them appropriately, which is quite a lot of effort for something with pretty little payoff.
So, on that front, I will have to request that you either pretty sharply reduce her skill in each style, or go all-in on one of your choosing and have an appreciable level of skill in it for her age. Especially considering the sheer breadth of skills she has, it's unreasonable to think that she would have the same level of experience in martial arts as someone her own age who has focused exclusively on martial arts, and even a child like that would be far from mastery with under a decade of experience under his belt.
Also, keep in mind that she's a little girl in Japan, and this is a roleplay about ghosts, so the odds of firearms coming into play at any point in time will be minuscule at best and nonexistent at worst.
Besides that, I don't have any huge issues. While she does seem to have the whole "perfect" feeling about her, in this roleplay specifically I don't have a major objection to that, because things like that don't matter as much in either the character dynamics half, or the horror half, so if you want to make a princess locked in an ivory tower, be my guest.
So yeah, just reach a decision on the martial arts debacle, and you're good to go.
Right, I'll work on that, then. Since I ultimately expect it won't be used much (If at all), would it do to say that she just has vague "Self-defense training" without defining a specific style? We'll assume it's a single style that she is somewhat decent in with the best trainer that money can buy, but I doubt we'll start going around describing specifically how the mantis style directly counters the tiger claw technique in this specific scenario and whatnot. Since it's not something that I, as a player, am capable of talking about, it might work if I just keep it nebulous.
The gun thing and the horse thing were actually both more for flavor than anything else. I honestly didn't expect to use either, like, at all. Unless we end up going around with super soakers loaded up with holy water, I guess.
In addition, I was kind of going for that 'perfect' feel. You've seen anime. I wanted to do something like that.