Horses conformation, color, and muscle toning?

Your mare is a bit to heavy in the neck and of course has a big belly which you can get rid of both with hard work, her neck is not to short for her breed and once you get rid of the belly her back will probably straighten out but she may not have any wither then.What I would do is ride her, she is not supposed to canter that is not a gate for a Paso Fina horse as long as she will Fino, Corto and Largo you have it made, that is what she is supposed to do. I saddle broke a Paso Fino mare for a lady in Tennessee and then she wanted me to train it to Largo but this mare did not have any Paso Fino gates and I told her you can not put in later what is not born into the horse. Your mare is pretty well build except for the things you already know about. To get her into shape work her in all 3 gates at least every other day for a month and she will look like a different horse.