I would think it has to do with the overall health of the tree. If there are no frogs to keep the wood eating insects down, the tree would still have the big hole in it at the end, perhaps?

No matter where I drop my villagers, all I get is "Confused" and "Refusing. Flower not ready." Is there a magical spot where I have to drop them in the two puddles? I've dropped them on the rock, in the water, near the tree. Nobody wants to save the poor frogs. Thanks for the help.

There is no magical spot. Just try several time in the puddles near the steps. Be sure that the stream is restored.

Stream is restored and I just spend the last five rain storms trying. They continue to refuse. Thanks for the suggestion, tho, Laurence.

This is the 2 places where I put my villagers. Here Waipi is confused because the stream is not restored yet:

It worked for me every time I did it. I know that there is a flower over there that , but maybe just experiment with where you drop your villagers. I like to have
But that's just me.