The second one is young but bone structure is bone structure. I see a nicely put together foal but I am no expert in anything other than what I like.
I like his shoulder angle, the way his neck ties in (though it looks high in one pic and nice in another - and I like his butt ;o).. He doesn't look butt high in the side view (though most foals do have a butt high stage) I can't tell if his dam is butt high for sure due to the uneven ground she is standing on (and these pics are far from ideal for conformational critiques) however she does look slightly sickle hocked. In one pic he looks slightly over at the knee but not in the other pics. In either case it is only slight and likely will correct within a very short time of growing. I don't see anything major at all that would be a deal breaker for me at least. I think he has a nice head too and the color is a bonus.
I like the first colt too but he isn't as flashy and I'd like to see better pictures of his neck. It is possible the second colt will roan too. Time will tell.
I still think you made a good choice