The rider does not need to grab the reins for balance when the seat is balanced. The rider's seat changes to match the horse's gait. A balanced seat is nice for the horse too, she doesn't have to worry about the rider hanging all over up there and can concentrate on the work out. The horse is collected when her forehand and her hindquarters are united. She is ready to move in any direction and at any gait at the request of her rider.
Conformation is the horse's build.
Each breed has conformation standards by which the breed is judged. Yes, but it's what you do with that attention to develop a relationship over the next several months that counts.