Thank you for the kind words and detailed comments! The locale stars were less grades, and more marked by how many creatures you collected there (which I am realizing is very unclear) If you just keep catching critters the stars will eventually fill in and it unlocks more critters to catch. The circles on the map scene are badges that you collect for catching all the critters.
I also agree on the battle mechanics. We actually had a 5 year old play it (was going for that roughly for target audience) and she only went to the stage to release the critters, otherwise just wanted to play at catching and with the fidget toys. I think leaning into that more and either dropping or significantly simplifying the battle system would be ideal.