Thank you for playing the game! No need to apologize, I like the questions that you ask )
And right - herons and frog-friend do not appear before your first croak. I did it this way to give players time to get used to jump controls.
I thought of game mechanics in this game that way:
Main mechanic - jumping; simple as that; you can't go far without jumping .
Secondary mechanic -croak (or more broadly, "make sound"). When you croak, you start seeing the direction in which you should jump. So croaking is required for progression but stays a secondary mechanic.
And for working together - it is even simpler - herons help with that. When you croak, you know the way, but you need to jump away from herons. And when you jump away, you may make mistakes, panic and forget where your friend is - so you need to croak again )
Hope you had some fun with the game nevertheless )