Discipline, individual hoof issues (genetic, injury) footing he’s working on, shouldn’t be a big deal to a competent farrier. Discipline is mostly irrelevant, unless you need to be skilled at applying sliders (and I won’t get into the issue of stacks in the gaited world )
thin soles, flat feet, shelly walls, tendency to run forward in LTLH growth, those are Horses. That should be covered in school. They’re not unique situations at all. If those things stump a farrier, he’s not competent.