As I said originally, their coat and condition are tops, if a bit fat.
That won't really affect their skeletal build, though, and as I see it (keep in mind I am always learning, and may be wrong. A few of the pictures are not ideal for conformation critique):
The silver bay is overall very heavily built for his size. His neck is thick and set on low with a steep shoulder. Neck also looks upside down or "ewe".
His hooves look steep/clubby and it's hard to tell but he may be back at the knee? Hard to see his feet, too (usually standing them on a hard surface like concrete is better to see these things).
He has a weak hip or lacking depth in that which is part of why his body is so long in proportion to the rest of him. His hind leg angles seem "ok" maybe tending to sickle-hocked?
He looks as though he should carry a good amount of muscle to stand up to moderate use for pleasure or performance showing.
I don't care much for his head shape with the bump high above the eyes, but he looks to have a pleasant expression. That is just aesthetics and that said I have horses myself that I am not wild about their head shape, however I will forgive a funky or plain head (to a degree) over bad legs any day.
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The roan is more concerning to me for his conformational defects:
His hind leg angles are far too straight and if they were angled properly he would stand sickle-hocked.
He also appears very downhill, and I'm guessing it won't change a lot given his age.
it looks like he stands over at the knee, too.
Less concerning/more aesthetic:
His neck is thick due to fat, but it also seems to be low-set but his shoulder angle is a little better than the first horse's.
His head is plain, but I like its shape better than the first one's by far. I also like his expression, he is quite cute.
I worry for his soundness more than the first horse just going by his legs, and would take it slowly on the driving conditioning and consult a vet as to supplements for his joints as well as keeping a good farrier close at hand (If I remember right, you are already doing this and kudos to you for that).
Good luck with your little men, hope you enjoy them. They are pretty colors and cute guys and I've also seen minis with worse faults that have stayed sound and been successful in the ring.
It's just something to keep in mind as you work with them.
If you search back on the Forum you can see where many members including myself have put up horses for critique which is nice to see what others see in "your" horses.
I've posted several in the last year or two. Thinking of putting up my yearling gelding again now that he's growing some.
Liz