It's not as absurd as it may seem. Eminem discussed the topic at one point, although I don't think any of them would fit the bill as a replacement for "redhead": https://www.youtube.com/watch?v=lPcR5RVXHMg
The trick is that assonance is sufficient for rap in contrast to a strictly true rhyme.
Finding a rhyme for orange
is as annoying as a squeaky door 'inge
If you ask why my floor that was white is now orange,
Well I quite like juice, and I last mopped my floor in July.
Came up with that one allll by myself.
porridge
Oh danger, orange, her hair may be, by the manger, quite, orange she sees, the fire burns bright, the ranger, he schemes, in death she finds evil Sir Granger's deeds.