Is there any way to know Mary Boleyn’s hair color/eye color? In the other boleyn girl book phillipa describes it as golden brown and grey eyes…

I don't think that we will ever know, conclusively, what Mary Boleyn looked like. Alison Weir points out that the portrait of Mary Boleyn at Hever Castle may not be Mary because the sitter is wearing ermine, which Mary would not have been allowed to because of the sumptuary laws, and also because there are various copies of this portrait which suggests that the sitter was an important person.
There is a suggestion that the Horenbout miniature featured in my post at could be Mary because Mary's husband, William Carey, was Horenbout's patron and the sitter's badge could be the Ormonde falcon.