Much better feet! Glad this girl got out of a bad situation. It seems so common around here that mini's just don't get trimmed as often as bigger horses, maybe people think because they don't ride them it doesn't matter as much? When I was on my pony buying quest last year I had come upon so many minis that just did not have very good care at all, and I passed on more than one because of obvious hoof issues from long overgrown slipper feet.
Heaves is kind of like horsey asthma, it can be regulated with proper management. For example, most horses with heaves do best outside at all times, except for short periods to feed or whatnot, they do best on pasture or fed on the ground or out of a slow feed net vs in a raised hay bunk where particles are likely to be inhaled, make sure hay is not dusty or moldy, if its a bit dusty water it down, outside is best as the dust is less likely to become overwhelming. Ride/exercise outside, or if you must make sure the indoor is thoroughly watered before riding. In some cases they will need steroids to keep it under control. You can usually manage them well if you are diligent about feeding them properly and keeping them out of dusty areas, they will most likely always be more prone to getting heaves though, and it may cause labored breathing because of the scar tissue that builds up in the lungs because of the allergic reaction that takes place. Ammonia (from urine soaked stalls) is bad for all horses to be breathing in, but it is particularly bad for these guys.
Once you manage their environment to fit their individual needs, adding work gradually is good for them, however, you need to be aware of how much they can take and when to stop, it's harder for them to catch their breath if they are still fighting against that allergic reaction.
My gelding has heaves, he is well managed, outside 24/7 fed on the ground or out of the slow feeder. I don't ride in dusty areas and he hasn't had an episode in nearly 8 years. He was fed moldy dusty round bales at a previous boarding facility which caused his initial heaves episode, and he is more prone to react to less than stellar hay ever since, but knock on wood, he hasn't had any issues since managing his environment and feed better.
Hope that helps!