Posting this in case someone else has same issue. 

I was able to get it done following THIS tutorial and adding the horse texture after the hair was added. 
No need to create new UV map and no errors. Am soooooo happy. 😊

Big thank you to everyone supporting and helping. Hugs.

Pic showing first, rough try for a dynamic mane created directly on the horse mesh. Horse with animations imported from Poser as Alembic file which kept all morphs.