RiT dye rather than paint

That looks like it worked out pretty well! Back in my more active days of collecting 1/6 scale figures, I knew folks who'd used Rit dye on bodies and clothes. Sometimes, the material being dyed wouldn't "take" or would turn an odd color. A few people experimented further and discovered other dyes made for nylon and similar materials which would sometimes work in those difficult cases. I think one brand was (cleverly named) Dylon.