A consistent Aristotelian Realist would have to abandon the idea that the universal, cat-ness, existed in the mind of God before he made particular cats. That’s close to Platonic forms. An alternative is that God knew and intended all the particular cats, not cat-ness, that would spring forth from the original pair, or however many he made in the beginning. But are the different colors of cats random happenstances that occur from a limited, preconceived selection? The idea of animals birthing body parts with genetically coded colors is pretty amazing. We can understand the physical circumstance that makes a rainbow appear, and how the colors are ordered according to frequency of light reflection, but that is a dynamic cause of color, not a genetic one.
God foreknew each cat’s color regardless of whether God chose specific colors to suit specific cats, or he front loaded the process and let it play out. I believe that foreknowledge of what color each particular thing would be and that colors only exist for each particular circumstance or thing and do not pre-exist in and of themselves is consistent with Aristotilian Realism.
A human artist is given a pre-existing palette with which he experiments. God, if I may be so bold, knows certainly what are good and proper characteristics for loving relationships between things, and tailors each natural compenent – animal, vegetable, and (atomic) mineral – to suit.
But did human nature pre-exist in the mind of God before particular humans? Gen. 1:26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth. Though “man” is plural, it is still specifically described as “them”, indicating particular people, not human nature. Adam was sinful before he reached his potential, but Christ was not. It is our nature to be like Christ. It pre-exists most particular people, but it doesn’t pre-exist Adam, except in God’s timeless and un-anthropomorphic mind, who knew who Christ would be.