Your pics of Shadow and Callie remind me of a pair we had at the kennel, same colours - they were named Orange and Black. I'm not kidding.

We always write the cats' names on the glass door, and make notes so we know who's who(which is the bigger one, the one with more white, etc)

So, for these two, under Orange we put "not Black" and under Black we wrote "not orange"

I work with goofy people in a goofy place with lots of wonderful furbabies!