As I mentioned above, an Entity Component System would have no issue solving this. You'd add the molecular frog components (foobigate and brozigate) to wherever

As I mentioned above, an Entity Component System would have no issue solving this. You'd add the molecular frog components (foobigate and brozigate) to wherever you create frog entities and then you'd also create and add a system that synchronizes between the entities that have pond frog components and these new components. None of the original code would change minus the instantiation function for a frog entity. Similarly simple change goes for the save format.