Thanks everyone for the input. Though I was driving another vehicle, I stopped by the Toyota dealer just for kicks today to see what they had to say. They suspect the fluids are actually leaking from the water pump even though the pink crusty residue is forming on the freeze plug. Possible I guess. The van only has 46000 miles so they were not sure why the water pump would have failed at that low a mileage. It’s also never been in freezing weather.
I was a little high on my cost estimate - still they estimated $650 to replace either the freeze plug or water pump - I know - an independent shop will do it for less. I always like to make repairs myself if I can but I won’t tackle a water pump in a transverse engine. Did that once and that was enough. Too tough without a lift and a good set of tools.