So Junior and R|Sakura really were destined to enter the tube instead of the clones. (I would actually consider this another point in favor of Sakura being cloned after the time rewind, since Clow did make a point of telling his daughter that she could change the future.)

The thing is, how would they have entered it in the first place? Did Yuuko put them there, or did Fei Wang? And for what purpose?

Also, is it wrong for me to think that Xiaolang's mysterious two years in Hong Kong were spent preparing to live in Japan with his childhood sweetheart for the rest of his life? I doubt his family would have been too pleased, and there's the difficulty of immigrating to consider (though I know little about Japan's immigration policies, so I could be wrong there).