i probably shouldn't bring this subject up again, but i want to point out a flaw in your logic.
"original" is a broad word with many meanings. the subjects in question, however, can be narrowed down to a more specific description, and there's a very clear cut definition for it.
"An original character is a character created that does not come from an existing copyright"
you can easily see most of the definitions for the word original alone don't make a lot of sense in the context of fictional characters. "Present or existing from the beginning; first or earliest" would rule out every character that weren't part of the original game. Lisa Hamilton and Mila are not DOA original characters because they weren't there at the beginning, but that's false. and nobody actually uses the word original to refer to "an eccentric or unusual person", as there are about a dozen other more natural sounding adjectives for that.
the same logic can be applied to the moveset. using the chronological definition, you could say it was "originally there", it has been around for longer than some others. but as far as originality is concerned... the definition of this noun is very focused, and this is what people often think about when they use/see the adjective original.
"the quality of being novel"
"freshness of aspect, design, or style"
"the quality of being special and interesting and not the same as anything or anyone else"
we all know Rachel's moveset was a derivative of Spartan's moveset, therefore it falls short on this department.
just like with Mila, Rig, Momiji, Phase 4 and Diego, Marie Rose has an original moveset because an overwhelming portion of it are moves exclusive to her only. not even Honoka managed to steal anything from it.
tl;dr: semantics, semantics
p.s. i'm all for Naotora not coming back just so i don't have to see people mistyping her name again. it's so easy to type a vowel twice, but you just had to give your L key a slap on the ass.
I've already mentioned that Rachel's moveset alone makes her originality older than that of Marie Rose/Mila/Rig for DOA, and she already is more original being in Ninja Gaiden.... another Team NINJA product. There is no doubt that she should not be considered a guest in the same way that Mai was a guest.
It's the very reason people expect Momiji and Rachel to be "cashcow DLC", but nobody says a thing about Mai... because she was definitely a guest. Because they have to negotiate with other developers to have guests in their game, it likely will not happen again; at least that's what they say. Rachel and Momiji are a totally different scenario.