Cursor horse.

No. Everyone needs a single cursor. The question might arise: "Why does our castle have a 2nd-level cursor creature (if we can call it that), while another castle has a 5th-level one, and a third castle doesn't even have it among its castle creatures?" Many might not like the castle cursor, but it might also work. It's unknown. It's better to just revert to the horse if the unicorn isn't appealing. Although, personally, I don't pay any attention to it.