This seems very well thought out and makes a good deal of sence. But I cant help but think... It the international statute of secrecy was just that... International, what could have been happening in other parts of the world to make them agree to it. in china for instance there was no great fear of magic and China was at the height of it's power since the Ming Dinasty. beleif in "magic" was still active but it had been made into stuff like astology. the only notable thing that could be connected with the statute of secrecy was increased cultural exchanges with the wast. Hiding "magic" in China seems to have happened in a different way. It seems that in China no effort was made to convince people magic did not exist. Instead they intertwined magic closer and closer into the chinese practices of astronomy and zodiac divination. slowly taking out everything that was asociated with magic as known by wizards. The chinese muggles believed in magic they just belived magic was something completely different then what it was in the wizarding world.

Can you imagine what it must have been like? *european wizards arrive to start discussing implementing the statute of secrecy*

Chinese wizards: Oh we took care of THAT Centuries ago.