Instead of having toxic body colors be random, have them be heritable, like regular fur colors. Programming-wise, perhaps have toxic colors correspond to regular fur colors (beige=yellow, chestnut=red, moss brown=green, etc.), so that there's just a toggle as to whether it is the bright toxic color or the regular color. This system would also let you could get intermediate colors, like toxic orange. White and black could serve as modifiers making pastel or darker (but still bright) colors.
It just doesn't make any sense that my toxic tribe is totally psychedelic (unless they've been grooming each other and are hallucinating).