Update:

I did the dip on Dec 03. I followed the recipe on theaquariumwiki - 2.1 gallons, 1/8 tsp PP, dip fish for 5 minutes.

I only dipped the tetra in the photograph, and the one with the sore on it's side. They definitely didn't seem to enjoy the experience, but they seem okay and have been eating. The parasite on the side of the photographed tetra is almost too small to see now. The sore on the other tetra still looks about the same, though I am sure those can take a while to heal. I am still treating with Paraguard to prevent secondary infection and prevent anything from spreading.