When the Animorphs started out, they weren't a group. Jake and Marco were best friends, Rachel and Cassie were best friends, Jake thought he had a crush on Cassie, Tobias was the loser, and through chance and circumstance they just happened to be all walking home together from the mall when Elfangor's ship landed at the construction site.
As it turns out, what race the characters are seems to be as random as them happening to become the Animorphs.
Think about it. The characters' race is mentioned briefly in the first one or two books when they're being described, and that's about it. MM3 is the only other book I recall race being mentioned, and its mentioning kind of shocked me just because KA never mentioned it otherwise. (I think David also jokes that Tobias is a "bird racist" in one of the books, but since it's birds and not people that doesn't really count.)
In fact, the only way you know what race the Animorphs are after the first few books is by looking at the models on the cover.
If K.A. was trying to make a statement at all as to race in the Animorphs, it would probably be that race really didn't matter to them, because they were working together to fight against the Yeerks for the freedom of the human race as a whole. They didn't care who was this color or that, who was disadvantaged and who wasn't, they were trying to accomplish something. That's a lesson from a kids book that a lot of adults could learn.