Here’s another vote for the Horse 2 to gain a unicorn makeover.
Noting the sub-topic about what unicorns look like, there is no such thing as a “standard” unicorn. Unicorns have looked like everything from rhinos in 400BC to antelope to wild asses, and only in the last century have they looked like horses (mostly because it makes things easy for Hollywood, one suspects). But the closest thing to an accepted standard for this era seems to be the heraldic unicorn. This would seem to be (and it does vary) a very slender horse-like animal. It has delicate cloven hooves like a deer, and a tuft of hair at each ankle. The tail is leonine, which is to say, a long length with quite short fur and a “flair” of longer hair at the end, much fuller than in a donkey or a cow. The neck should be longer and less muscular than a horse’s, and the muzzle is more delicate: if you morphed from a horse to a deer and stopped about halfway, that’d be about right. The horn varies quite a bit, but is generally straight with spiraled fluting, and about one to two times as long as the animal’s head.
Gonna need a lot of dials here:)