Well, that is a lot of questions, lollol and welcome to the forum:)
First - here are two links to two great gaited horse women.
Liz Graves has been the GoTo on gaited horses for many years. https://lizgraves.org
Ivy is fairly new but I have never read any bad reviews about her:) https://ivyshorses.com/home/about/
I am a lifelong trail rider and have had TWH's since 1990.
1. Conformation. They can also be a bit cow hocked. Splay footed to varying degrees is very common but no big deal unless they toed out so far that it affects the tendons as they get up in years.
1.1. Some TWH's can develop hock issues in their senior years.
2. The worst health issue that is common is insulin resistance, therefore founder. TWH's are a thrifty breed so not over feeding or filling them full of unhealthy starches (like sweet feed) is important.
3. The only difference in riding (IMO) is what you do to get the horse into its intermediate gait -- which ther ARE different intermediate gaits:)
I am a western style rider, so the reins stay in one hand (my trail Walkers are/were barely touch their necks sensitive at neck reining:). When I want the intermediate gait, I drop the reins down and sit back on my pockets.
I have never had issues with any of my Walking Horses gait u g unless they needed the chiropractor
, then they would trot. I've read about a lot of PTWH's that don't gait and I still think it's either skeletal issue, lack of knowledge of the rider, or the TWH isn't 100% TWH.
4. Head Nod: up/down means the horse is performing the signature running walk. It can vary from barely visible to so busy the ears flop. My TWH that performs the best champagne-smooth run walk in the planet barely bobs his head.
4.1. Side-to-side head movement means the horse is performing a stepping pace, pace, saddle rack. Any if which can either shake the chaos off your teeth or be as smooth as a running walk - much depending on the structure of the horse.
5. Head set is whatever the horse was born with - no unnatural man made "peanut rollers".
My 25 year old TWH's registered name is "Ultra's Sky Gazer" because he was born with his head in the air and it's still there; he is also the champagne-smooth run Walker:)
To see any natural movements, head/neck sets, watch the horse in a decent sized pasture:)
6. I hVe never cantered my Walkers simply because I got u to Walking Horses when I was older and wanted to enjoy the glide:). However, my Step pacer was a hard lateral pacer in the pasture and never cantered at Liberty.
The fella who saddle racks and sometimes run-walks at Liberty will lope thrush the pasture like a Walt/trot horse.
The 25 yr old with the champagne-smooth run walk has a breathtaking rocking chair canter, at Liberty, that he was born with.
7. IMO ANY horse that cross canters has a structural health issue that needs addressed. Or it could even be poor trimming or poor shoeing.
8. I live in the "Cradle of Walking Horse Country". Around here, we simply say we have "Walking Horses" when asked:)
9. In conclusion, I can understNd why you are confused and have received/read different theories, lol. Much simply depends on the horse, it's gene pool, and how the horse is built.
The basics of training, hoof and health care re the same as any other horse. It's when one want to engage a gaited horse into their intermediate gait that things become different:)
Also, do NOT
let anyone bamboozle you into thinking your Walking Horse needs to be trimmed or shod different because it is a Walking Horse. They get trimmed and shod according to what their hooves are asking for, just like any other horse.
I hate to keep throwing my 25 yr old into this conversation but -- he performs that champagne -smooth running walk barefoot (the bulk of his life) and with one hoof a Less-Than-Grade-1 club hoof (diagnosed by a vet). He's never been lame a day in his life and he's been with me since he was 2-1/2:)