Very few diseases can be transmitted between humans and fish.
It is more likely the fish tank did not have proper setup for "a lot of goldfish". Goldfish are messy eaters and they produce tons of ammonia waste. It is recommended to have minimal 20 gallon of water for a single fancy goldfish, and extra 10 gallon for every additional. If it is common goldfish, then the minimal requirement goes up to 40 gallon, and additional 15 gallon is needed for every extra common goldfish. The filter system required for goldfish tanks also must be sufficient enough to handle the ammonia produced by the fish. Ammonia produced by fish through their gills on a constant basis and it is also produced from their organic waste as well as from the leftover fish food in the tank. It is toxic to the fish.
Overfeeding is another common cause for fish dying, because it can produce ammonia spike even in a well established aquarium. With all the kids keep feeding them, it is likely to be one of the causes.
It could be either overstock, under-filtered, or overfeeding, or all of them combined that killed the fish.
As for playing with the fish, most fish will not interact with the human, but many fish which have get used to the feeding routine will display certain behaviors such as following you as you walk by the tank.
