Unless things have drastically changed during the past 14 days on patreon builds , you actually were able to write whatever haircolor you want using the hair dye item attained from shops. Eye and fur colors may just not be a priority among a bazillion things to do.
I meant more in character creation at the start than hair dye item. Although if hair dye allows us to enter whatever color we want through text input... I see even less reason to not allow it at character creation, since I thought it was coding reason to only allow us a fixed number of color choices.