I used to do it in my younger days, getting unhandled 3 or 4 yo Fell ponies to train and eventually sell on. I really enjoyed doing it.
I did know my limits though, I wouldn't have taken on a young blood horse.
To be honest I found them far less trouble than something that had been messed with...
I still feel a bit guilty that years ago my pony killed a rabbit on a roadside verge in the middle of the day. Stood on it at a canter rather than rearing at the sight.
When, in my youth, I was around people that bred Shires, the 2yos would be harnessed up and spend time walking next to the experienced ones which were hitched to a plough or vehicle.
Keep well away from these people. They have some crazy ideas. Sometimes the heel does need to be taken back if it is getting crushed but I wouldn't let these people anywhere near a pony of mine.
I've always made sure my foal was well away and out of earshot of the mare for a couple of months when weaned. It takes them both some time to be used to being apart. Make sure the foal has company of other youngsters.
I wouldn't take her to the clinic. Go without her ,you will still learn stuff.