I took a while responding because I don't have any experience with tadpoles. I looked up bloating, and apparently sometimes it can happen because tads injest air along with food. Not feeding for a while can help apparently.
As far as the red leg, I hope the tads will be okay. They're delicate and even my full grown frog has responded badly to medicine before. Hopefully most will pull through.

Edit: You seem to know what you're doing medication wise. If you have tips or a formula for dosing frogs with red leg I'd really love to hear it if you feel comfortable sharing. (Yes, taking frogs to vets is often the best option but so many people here have no access to frog vets or their vet just died or something.)