I know you're doing you're doing what you think is best for your animals, and being corrected at every turn must be frustrating, but the fact of the matter is they DO NOT look healthy. The smaller one is much too skinny, and newts should never show the kind of skin blotching he's exhibiting. Inability to shed is a bad sign. Just because they've been alive for a year does not mean they are healthy. Animals can be quite tough and survive in harsh conditions for a long time. Their health and immunity will continue to degrade till one day it just gives out.
The point is, you're keeping the newts alive, but not well. One year should have been more than enough time for a wild caught newt to recover adequately. They should have been fully aquatic by now, and You should not be having a skinny undereating newt, that just means it's sick. I've had my new set for 5 months now. I kept them as a child in the way you did and after keeping my new set well, it's a marvel to see them at full potential. HEALTHY newts should be plump, have marked muscle development, be active swimmers and feed confidently. Mine have progressed from being skinny things that could barely take some tubifex worms to fit, strong animals that can easily eat a 3 inch earthworm.
One year ago you were told to increase the water volume to 10 gallons. I really recommend doing that immediately. The newts bad health can probably be directly attributed to your water quality, as it's unfiltered and such a small volume. If you can't get live plants to stay alive try a sponge filter as it will provide little current and will clean your tank of toxins.
We don't mean to be overly critical here, we're just trying to ensure your newts have the best environment and health, so you can enjoy them longer. You said if you were doing something wrong they would be dead, and the fact is, you are doing something wrong and they are dying, though slowly. It's not too late to remedy that though. Provide adequate conditions and you'll marvel at how much they improve, and enjoy them for years to come.