Oh wow ! I read your thread, and I've been going through the same thing ! It's almost the same scenario. My two newest additions (a mare and stallion) came from an older couple who knew nothing about horses, even less about stallions !
The mare was not too bad, as she is sweet by nature and the former owner's grandchildren would brush her and braid her mane... but the stallion... I was told he had not been groomed or had his hoofs cleaned out very often. And it was true ! Hoofs were horribly long... they must not have been trimmed for a year or two. I called my farrier in emergency. Thankfully, the hoof structure was ok for the stallion. The mare's is a bit deformed, although it's getting better with each trim she gets.
When I got them at my place, I thought it was all a big mistake... But now I realize it was not.
I've had them for nearly 10 months, and have worked lots of things with them since... Like everyone else was saying, it definitely takes lots of patience and baby steps.
There is one saying I just love: Act like you have 15 minutes, it will take a day. Act like you have a day, and it will only take you 15 minutes.
I've been using it all through the process and it works tremendously well ! Now, I can pick up Jumper's hoofs and he won't blink an eye. And I can put a blanket around him without seeing him flinch.
Keep at it, perseverance is the key. Just watch your horses, and learn from them. You can do this !