I did not manage to do anything interesting with my toys. I tried using this small piano (picture 1) but I could not open the case as the screws were glued.
I also had this small phone that played songs whenever a button was pressed. I managed to open its case but I could not change the sounds in any way. I attached a video of me trying to change the sound with alligator clips and needles.
It was still a really interesting task, as I now have a better idea on how these toys function. It also gave me an idea on how to use the phone case for one of my own circuits (using piezo buzzers).