horse racing game

Need some help about it…
I want make a VR game about “Palio” from Siena, Italy. But i need some tricks…
1.Horse AI controlled must be character or vehicle? if i use it as vehicle in some spline system tools i must set simulate physic on mesh component, but when the game starts the horse falls to the ground like a sack of potatoes…what’s wrong?
2. there’s some tutorial that can help me about ride an animal in VR?
3. Any tips on collision to get the jockey off the horse?