­Trained Pronghorn - though I suppose antelope and giraffe are equally distant in their relation to pronghorns, it looks closer to the already established Antelope.

The pronghorn's closest living relative is the giraffe. That being said, giraffes have yet to appear in Magic, so who knows what creature type they'd receive.

From my understanding, among the ruminant branches, the pecora infraorder splits into two brances, one branch having giraffidae and the pronghorn, with the other branch having deer and another branch that splits into bovidae (which would include animals called antelope) and a branch for musk deer.

There is an okapi in Magic that's an antelope, and frankly, this kind of incorrect reflection/choice is unacceptable, especially when dog, wolf, and coyote are all separated (but somehow raccoon dogs, which are more closely related to foxes, end up as dogs). Ignorance of the audience shouldn't be an excuse, especially since these are almost never have in-game mechanical tribal relevance. And, for Dogs and Wolves, would tribal relevance between the two even be a gameplay problem?