@Hetty, you know I like to ask questions, but this question (s) is probably a stupid one.
I have plumeria, that when growing new tips, those young tips (and even the leaf-stems) will be almost white and some are distinctly pink. Have you noticed this with some of your plants? Are those colors possibly a tip-off for the flower colors? I have seen for years that the Scott Pratt has almost burgundy colored new tips/leaves, and its an intense red.