Hi there! First off, thanks for playing and sticking with it. I'm sorry it frustrated you.
I assure you, there are ways to deduce the answers to all the questions you've asked. For example...
*SPOILERS*
The earring isn't the only way to confirm that the laughing girl was the one who tied Rosie's shoelaces together. She also has grass stains on her top, and there is a path of flattened grass leading under the bench.
*END OF SPOILERS*
The full game will include a hint system, but we haven't written the hints yet. In the meantime, I recommend this let's play, if you're interested:
I don't know this player, but they do a good job of voicing their thought process, and, while they don't pick up on every clue's significance, they come close enough, IIRC (it's been a while since I watched it).
However, if you'd prefer me to tell you how a specific part can be deduced, I don't mind doing that. Just let me know here (I just wish itch would let me use proper spoiler tags!).
Lastly, you're right that even by the second scenario, the game is pretty tough. It isn't just you. Maybe it's a misstep on our part. We'll see!
All the best!