How to get a starter cat to throw it's hidden fur

[sneakpastu Resident]

Have you tried this?

Have you unboxed the offspring and paired them to one of the parents? Sometimes it does not appear until the next generation.

You might want to try Balinese - Seal Lynx. I know that might seem a bit not with convention, but I have had moderate success getting the hidden fur and a few other traits. You will want a pure 9T though...meaning it's been a 9T for several generations (not just what is shown on the Pedigree).