So... are all people in Kowloon 2.0 clones of people who originally lived in Kowloon 1.0 and/or are they physically incompatible with people from the outside? That would explain the fairytale-like "don't eat their food" bit... Also, kudos to the author for revealing jaw-dropping plot points in such a nonchalant way, haha.
Also, there's a lot of things to appreciate this amazing series for, and one of them is focusing on both heterosexual and homosexual pairings. That's pretty uncommon, especially since all of these characters are decently fleshed-out.