I only recently did a successful recolor but it was clothing. Can I have some advice on recoloring hair? I only have GIMP because it's free and I can only use free programs. Any help will be greatly appreciated.

Can someone make Usurper King Zant from Legend of Zelda: Twilight Princess, Alex Louis Armstrong from Fullmetal Alchemist, Nergal Jr., Jack O' Lantern, Pinface, or Lord Pain from Grim Adventures of Billy and Mandy, Jorgen von Strangle from Fairly Odd Parents, Syrus Truesdale/Sho Marufuji from Yu-Gi-Oh GX, Rocky Horror from The Rocky Horror Picture Show, Mayor Buckman from 2001 Maniacs, or Count Graf von Krolock from Tanz der Vampire?