I might be too late…
This is regarding the TWH/Appy horse who wasn’t doing well in the PPE. Make sure you have a neurological exam done. This should be crossing the front feet, then pulling out the hind legs to the side and seeing how long it takes for the horse to replace the foot, not just pulling the tail. If there is any delay, and you’ll be able to see it, there’s a neurological issue, most likely Wobbler’s Syndrome.
The reason I say this is that Wobbler’s is a common problem with TWH’s. In my experience about 40% of the walkers I’ve looked at had it. It can also come across as lameness.
I didn’t want to post this with the rest because as soon as I mention Wobbler’s, gaited horse people get upset and deny it.
Good luck, he looks like a nice horse in the video.