I saw you recently removed Jerimiah from the Morgan page, for evidence simply replay the mission and hold L2/LT BEFORE getting too close and you'll see he's a flaxen Chestnut Morgan, thought id just add that thank you for you contributions to this wiki, hope to hear back
I haven’t been able to do that, but I think it’s highly likely that Jeremiah is the horse you describe. Jeremiah’s coat is identical to the Flaxen Chestnut Morgan, and both his build and stats are also the same. I really can’t think what else Jeremiah is other than a seemingly giant Morgan, so I’ll re-add it. Thanks for finding this out!