I haven't noticed a martingale being interchangeable with a prong collar, but if the martingale works just as well that's a good thing
Keep training training training, try to get away from relying on the training aids altogether
Have you tried a halti? I've had really good luck with them when fitted properly. I use the leash on the dead ring, I haven't noticed any benefit from the loop around the muzzle being allowed to tighten.