Why the girl hair colour

[MANoBadAssGar Jr.]

Touhou character hairs and head things are the main if not the sole identifying factor most of the time to tell who is who apart from canon attire.
Obviously their hair colour not just randomly picked from rainbow roulette, or at least not out of whim mostly. So what things taken into consideration when deciding hair colour for the character? here's my take on guess

• Reimu (Windows)
  She's a genuine Japanese girl i guess. Dunno why it sometime brown-ish, lighting probably.
• Marisa (Windōws)
  Her name sounds like Marissa, a western name, so she bleach her hair blonde, as part of her rebellious phase act. and her eye too while she at it because why not.
• Rumia
  They like, "look, this is an eastern game with western demon girls".
• Cirno
  Obviously ice theme i guess.
• Meiling
  Her name probably, so why her name? like, telling this is where the red start! maybe
• Sakuya
  ........dunno, stress?
• Patchoulli (i probably misspelled her name, got tired recheck every time)
  I seriously had no idea, you guys tell me.
• Remilia
  The boss of the whole scarlet game, telling you any bizzarity is possible in this game.
• Flandre
  Now this is vampire! don't thought too much about her wing
  
  Honorable mention
  
  • Small fry big fairy
    Nature typically depicted as green.
  • Little devil in scarlet devil mansion
    Now we're talking!
    
    
• Letty
  She just like shaved ice, so grape syrup would look good on her.
• Chen
  She's orange. I lied.
• Prismriver sisters
  Blonde in black are cool, or just to look cool as the eldest.
  Brown in red look average, sly one usually like that.
  Light blue in pink looks elegant & calming, turn out she's maniac.
• Alice
  The another certain Alice usually blonde. or this one just actually foreigner.
• Youmu
  Konpaku lineage have white hair. I just made that up.
• Yuyuko
  She's cosplaying sakura tree.
• Ran
  That's not hair, that's fur.
• Yukarin
  haha a blonde purple.
  
  
• Mystia
  Yakitori gotta looks yummy, pink is yummy. Pink yakitori are questionable though.
• Wriggle
  Thats a grass camo, she's trauma from abduction.
• Keine
  She made herself looks like a funkster by dyeing part of her hair with light blue.
• Tewi
  When human aged, their hair turn white, when demonic animal aged, their fur turn black. ......what?......
• Eirin
  She's just old, pls no bully.
• Kaguya
  Like traditional kaguya pretty plain
• Green Keine
  Her dress mystically became green, so she uses green hair dyes. gotta match your dress, man!
• Mokou
  She has aged, that's normal. wait.........
  
  
• Kazami-san (kyaaaaaaaa)
  Look at that beyond elegant wavy green hair, her gorgeous intimidating red eyes, scary beatiful smile, there's absolutely nothing wrong, a beyond perfect creature.
  yeah? why hair colour? i dunno, but she looks good in that so don't bother with minor detail pls.
• Komachi
  She dye it, for camouflage when naping in red spider lily field.
• Hina
  Taking too much green thing. Not weed, just sayin
• Momiji
  That's not hair, That's fur. Also, she's bite.
• Kogasa
  To match her not-red eyes. why her eye colour? that's different topic, silly.
• Kasen
  Roses are red, Kasen are pink, one armed hermit are horned & wild. i.......i dunno.......
• Wakasagihime
  If she had red hair Touhou will get sued, so she had blue hair instead for total denial & opposition. Safety first.

What do you guys think? are there any character that you think not fit very well with their hair colour? or why it goes very well with them? Not just the above mentioned, but every cast.

[Sophilia]

It's very much a case of Gensokyo's First Law.  Do we on the outside believe in these weird hair colors?  We don't, so guess where they end up!

That said when it comes to specific girls Akyuu's always seemed a throwback to the purple haired humans of PC-98 era.  Her name is on the official PC-98 era soundtracks, after all.

[MANoBadAssGar Jr.]

Shit, i just realized i forgot Reisen in IN section

Reisen
for sexual appeal

[shockdude]

• Sakuya
  ........dunno, stress?

ok this one made me laugh. Well done.

[the old guy]

Patchoulli:
Sign of Lineage, or hair dye.

Youmu:
Half-Ghost.

Yuyuko:
Canonically, she had a darker shade of hair color when she was living. But now, it serves as symbolism for Cherry Blossoms.

Yukari:
Is Maribel Hearn. Who is an westerner.

Kaguya:
Most beautiful women in the world, so she never ages.

Mokou:
Slightly old age (This is because she canonically had black hair when she was a kid).

[andykhang]

Kaguya: Not to mention she's a Lunarian in the first place. Probably because Mokou is a human that her hair turned like that due to stress of intense power.

[MANoBadAssGar Jr.]

If so, then hourai elixir must have some bullshit in it, or that one elixir accidentally had eirin shenanigan. or human body reaction are faster than the initial effect of hourai.

A bit serious, possibly Moko dark hair from the past was dyed somehow someway, and her natural hair colour are really white. The elixir restore it. Her red eyes too.

And that also kinda clarify that spell thing(or probably just some) & flight capabilities are wholly tied to mind or soul and doesn't require alteration to physical body. Assume Moko learn all her flamey thing after becoming hourai person.
or she self re-acquire the thing after each reset (honestly it's more like reset rather than resurrection), such a chore

or hair turning white & eyes turning red doesn't count as "damaging" thus updated as "initial state".

[the old guy]

A bit serious, possibly Moko dark hair from the past was dyed somehow someway, and her natural hair colour are really white. The elixir restore it. Her red eyes too.

I highly doubt it, black is a pretty common hair color for Japanese people. And Mokou is Japanese.