I think the wave of dog diarrhea that swept through is done with and everything seems to be back to normal now. Nala ended up getting some IV fluids at the vet last week as a preventive measure to make sure she didn't get dehydrated and a course of metronidazole just in case. She seems to be back to her regular self now.
They were all very happy to get out to the dog park yesterday afternoon for the first time in over a week. Much running and ball chasing went on. Even Mel got into the action playing chase games with some of the other dogs.
Back to life as usual now. *whew*