So, the last pictures are of the hind feet, right?
They almost appear to have a negative palmer angle,and the bars, esp are badly over grown, with the first baring surface on the right bar (picture orientation ), almost seeming to be in the middle of that bar.
Heels appear un even, and the frog is pulled forward, thus some hoof mapping to determine the true apex of the frog, and the widest part of the hoof is needed.
You can google ELPO (equine lameness prevention organization, and there are two good videos on this subject, plus written info
I think the trim is paramount, and then decide as to what special shoing might or might not help. Shoes will lock in any pathology, so that mapping should be done,, and then determine goals that are attainable
Far as any special shoing, that your farrier does not routinely carry, I have always bought those things, after asking if my farrier was comfortable in applying them
In my case, it was for my IR horse, that got set back very badly, by a professional I trusted), and where barefoot and hoof boot rehabilitation alone were not working
I special ordered several different support shoing, and found what worked best in the end, including glue on shoes, after finding out if my farrier was willing to apply them.
Thrush is a pastern dermatitis, caused by various organisms so what works in one case,well might not in another. They can be bacterial, fungal and even viral or caused by a mite.
Thus, in cases that are difficult to resolve, using something that is at least both anti bacterial and anti fungal is a good start. De worm with Ivermectin, in case a mite is the problem
Most of the organisms causing scratches are opportunistic, meaning they are not primary invaders, but need some breach in the skin to invade.
Photosynthesis on white feet, dew, walking through things like thistles, or any other skin irritant, open the way for scratches
