What a lovely horse at liberty. And I do like the gentle way the trainer has of putting the reins over the head and neck. Hhhhmm unless that suggests the horse wouldn't tolerate having them flipped blithely over. After that ... it looks as if he has to steady both the pony and the saddle for mounting which suggests you might not be able just to hop on and ride away.
Don't you suppose the "mouth thing" is from rushing the training? Do you think in a slower training program this same pony would move more naturally with a happier mouth? There really is nothing inherently wrong with using a bit. It's the hands on the other end that turn into an instrument of torture. Nancy