Congrats on getting yourself better. Information helps, but you've got to apply it and not everyone does.

Regarding #1: Interesting observation about the horse and camel riding. However, I think there's more hip extension involved in both of those activities. I imagine there's also more muscle engagement in both too. Still an interesting point though. Makes me wonder if there's middle ground, regarding hip extension, while sitting. People typically talk about sitting vs standing at desks. I wonder if there's a place for chairs that sit higher off the ground to allow for more hip extension and sitting on the edge.

All speculation on my part.