First of all, I want to say that you did a great job summarizing things. But for the MFMM pattern, it’s a bit debatable in my opinion. If Oda use the same MFMM pattern again, isn’t it too predictable? Not to mention that we have to think widely also; 10 male - 3 females. The females are still not comparable with 10 males, so I suggest 9 males & 4 females. And the other thing is merchandise related stuff. Just imagine that having 13 main members, where Luffy is in the middle, then 6-6 members on each side; each side consists of 4 male & 2 females. This happened so much already before Jinbe joined the crew, with the 9 members.
Another thing for sure is about “bad luck”. It’s a myth in Pirate world that bringing woman/women to the crew brings bad luck. Hence, Nami & Robin’s epithet are more on the bad side than good side (Burglar Cat & Devil Child). What is another bad luck? Number 4, which is read as “shi”, the same like how Japanese pronounce “death”.
Additional interesting thing to note is about their powerset. Nami is a non-DF user, Robin is a Paramecia DF user, and Yamato is (most probably) a Zoan DF user. What’s left is a female, and only Logia user in the crew. If Yamato joins, there are 3 Paramecia users, 2 Zoan users, and that’s left is a Logia user. I think that the Logia is a female, is what has Oda been hinting all time; almost every single Logia user is men, the only Logia user which is a woman is Monet and she is presumed dead. And I agree that although Yamato may not fit the YZ pattern, she might be changing her name into “Oden” or “Ouyama”, as we can see in current chapter that Yamato wants to severe the chains that bound her with Kaido, and I believe that is her identity as Kaido’s “son”.
for the colour theory, I might have crazy theory but so far it’s reasonable. The 6 main colours of the rainbow is coincidentally the 6 “human” members of the Straw Hat:
Luffy - Red
Nami - Orange
Usopp - Yellow
Zoro - Green
Sanji - Blue
Robin - Violet
What I say as “human” is human both inside and out; Franky & Brook may be human before, but they are not fully human inside and out. Brook’s colour is Black & White. I have presumed, that Black & White represents “Stronger” & “Weaker”. Let’s see from the example:
Chopper - pink (lighter shade of red)
Franky - cyan (lighter shade of blue)
Why is that so? Because Chopper is definitely weaker than Luffy, and Franky is definitely weaker than Sanji. The most prominent example currently is Jinbe’s signature colour, which is Ochre; in Japanese it’s “黄土色” (Oudoiro) or “Yellow earth colour”. I presume Jinbe’s signature colour belongs to yellow part, and Ochre is a deeper shade of yellow. And what is it? Jinbe is stronger than Usopp. Why Oda chose Ochre, an uncommon colour to represent Jinbe? Oda should’ve chosen just plain Brown “茶色” (Chairo) but Oda chose Ochre as a sign that Ochre is deeper shade of Yellow, because Jinbe is stronger than Usopp. So all that’s left is purple, green, and orange.
I believe that for green part, it must be lighter shade of green, because Zoro’s colour is green & the one who represents light shade of green must be weaker than Zoro. Coincidentally, the “lighter” shades of colours are the Monster Trio: Luffy, Zoro, Sanji; Red, Green, Blue. I still have no idea whether the one who represents violet will be weaker/stronger than Robin because Robin is currently among the top 5 fighters in SHP, although Robin is more brain than brawl. But for orange part, it’s most definitely the deeper shade of orange which I presume: Yamato.
So the colour part is most likely like this:
So the ones left are purple & green. I suggest Yamato might be deeper shade of orange because her horns are shades of red to orange, and she wears red pants.