OK, Melafix is a mild natural bactericide and Pimafix is a mild fungicide with some effect against internal bacteria. Also, Pimafix will kill the white little Planaria worms that inhabit many tanks (live of detritus); so if you see some white little things floating around do not worry.
Both medications can be used together, so what you will do is premix like a gallon of it in dechlorinated water according to label instructions. Then use that medicating solution in pond area and/or frog's baths. Once mixed you can store solution in a dark place. You will replace it 100% daily and treat for 7 days. If a frog is to weak or does not visit the medicated solution; gently place it on it (level to it's chin is fine) and keep frog there for around 20 minutes ea. day.
Le us know how things go and hopefully frogs will improve some. Have no idea of any possible interaction/interference with the Lamasil treatment; so would complete that before doing the Melafix/Pimafix bath. Hope the frogs do recover, but if internal organs have been damaged, we can't repair that. Good luck!