I agree with IEI-Fe
I have not seen much of Belle, but I have seen enough to get an idea of her type. She is quite reserved in interviews but uses very good Fe when she talks. I remember seeing a lot of people commenting on how surprised they were that they actually liked her when she was being natural. She also knows how to really milk opportunities she gets and make them last. Not to mention that she has proven she knows when initiative is appropriate (not revealing anything that could be considered hardcore porn until recently I think). Seems very much like Ni lead to me.
She sort of sucks people in with her cutesy raunchy charm and then milks them as long as she can. Very NiFe. Not to mention she needs good 4D Fi to keep people around after luring them with her creative Fe.
And that “SEI” persona people point out probably isn’t even much of a persona. If you look up her house you can see that yes, she is very attentive to environmental aesthetics, but it’s more fable-like and lacks that Si homeyness. I have actually imagined creating extremely similar (almost identical) environments for myself and would love to if I could. Don’t know much about DCNH yet, but maybe harmonizing subtype?
Yeah, I might actually go with IEI-H for her.