Elfangor acquires several men and uses the frolis maneuver. It's in Andalite Chronicles that we learn the name for what Ax does.
Big cats are mostly compatible as hybrids. There's also an instance of wolves and coyotes interbreeding due to shortage of habitat.
Mind you the frolis maneuver may not actually work that way, but if four different humans can be combined in one morph then it's safe to assume that you could combine DNA of creatures from the same group as well.