I think your idea of squatting toilets is a good one. Though I would go one further.
How about some kind of platform that you can retrofit to sitting toilets? That way if you wanted to squat you could pull out the platform and simply place your feet either side of the bowl.
I have heard about people throwing their paper into the garbage and it is gross! A friend of mine said they once had foreign exchange students staying with them and no matter how many times my friend's family told them to throw the paper in the toilet. They just couldn't get their heads around it.
Does the third sign down on the left suggest no fishing? I'd love to meet the person that is designed for 🤣😂🤣😂🤣
Yes, it's an attempt of making the sign funny. I wonder if the intended audience finds it funny though :-)
I think the opposite approach would be much easier and simpler; install a squatting toilet, and then make some arrangement with a sitting ring that can be folded down when needed. In my head it's such a simple easy concept that I almost find it weird if it doesn't exist any toilets like that.