Your last sketch looks like an inverse of what a goon would probably look like in reality. When pouncing, it could utilize its hind legs, which would then need to be considerably oversized to provide enough leverage/muscle power in order to facilitate a long-range jump capability, which the dragoon definitely has. Hence, you could exchange the front pair of legs for the hind one. There is no reason for the front pair of legs to exhibit excessive signs of hypertrophy - after all, the goon doesn't use these to attack, it uses its jaws instead.