Overlay and armor bugs

The reason I am doing 2 bugs types is because I am making armor that gives an overlay. Let's get going. Armor with one 64×64 texture file looks bugged as opposed to two 64×32 texture files. Overlays base textures are cut off. And semi-transparent overlays make the hotbar completely invisible behind them. I have uploaded the workspace. In the image below, to the left is the bugged armor on the armor stand, and to the right is a mob with the same model as the armor.