Have you taken lessons-so you don't have to train a 5 yr. Old? Or are you wanting to progress slowly w/the horse over the years? Either of the bays could probably get there, but it will be a lot of training. You would get a better answer if we had a little background on your experience, if you're at a show barn, if you have a trainer lined up and/or a riding instructor that is helping you find the "right" horse for your goals. Are you just going for jumping or will there be some dressage or maybe even 3-day eventing?
Boots, I noticed those marks as well. They could be pixels on the picture, but it's definitely possible that they're from pin firing. If you look more closely, the marks are also on his LF hoof, so it could just be the picture.
I would eliminate the third as well. The critique picture isn't great, but he's built wayyy too downhill for my taste.
The mare would be my pick. She has a lovely shoulder on her and a solid build, with the exception of being slightly downhill.
I wouldn't totally eliminate the first gelding if he has a better temperament and more training than the mare.
Of the three, horse #1 is very classic.. and almost looks like a 'chaser. He is a bit long.. and he is very slender and muscular.. looks like he needs to be let down. #2 is also a pretty nice horse but I would want an Xray of that right front knee. It looks to have a bit more going on than "bucked" knee. Number three is not very good behind.. poor leg angles.. and is very slight of build.
Number 1 needs his feet done better behind (or needs shoes behind). His heels are very low and it looks like his feet have worn down.. likle someone just pulled the shoes and let him go.
PS: I would not worry about pin firing. It used to be all horses at the track came out pin fired. I foxhunted with a few of those and they were fine.. it is just something done to deal with bucked shins (and it has been discovered that almost every 2 year old in training will get bucked shins even if they show no soreness.. it is part of bone remodeling for the work they have them doing).
At one time almost all race horses were pin fired to try to prevent bucked shins. It doesn't seem to work.. but some still do it.
There's something about #1... he has his faults for sure but I am drawn to him. #2 is ok... cute and chestnut which to me is a big plus, but she doesn't draw my attention. #3 doesn't even deserve a second look to me, plain and awkward... though it might be because the photo is horrible.
Both number 1 & 2 have sacro issues and soreness. Number 2 also looks quite weak behind and knees look terrible.
My pick would be 1 or 3. The pic of 3 is not a good one but I would not rule him out. I like his neck and shoulder and hindquarters, not the best angle though. Would not make an Olympic horse by conformation but it's all about how they ride huh....
I do like number 1 but I'd be worried about the sacro. Ride them then decide........... I personally would need a better pic of number 3!