Great quiz! I think that ShangriLa, with no space in between, should work as a type in. I often type things in without a space because it is faster but the hyphen makes it so no space in between doesn't work.
Just to be that guy, Chungking / Chongqing is another major city long known in the West. After government reorganization it is technically the most populous city on Earth within city limits. The city limits are, however, over 80,000 square kilometers. That's a "city" larger than 12 of the 50 states in the U.S.A. and more than 40% of the nations in the world. Maine and Austria are the closest in size, respectively.
I'd back this idea. Chongqing was even a temporary capital during the Japanese invasion, so it certainly seems to be a better candidate than Haikou for inclusion in this quiz.
(I'm a geography nerd like most of you here but I never found this city in quizzes alike)
Every time I take a quiz involving Chinese cities, I forget about Chengdu. Then when the quiz is over, I see the answers and think, "Ah, Chengdu!".
It's a massive city with a long history and yet. . .my brain refuses to remember it.
My apologies to the residents of Chengdu but my subconscious clearly refuses to believe you exist.
Shangri-La renamed recently to attract tourists, so it was the only one that slipped my mind.