Can someone help me?

I am all confused.
I've heard that Syaoran has a twin brother. Is that the cone au his real twin?
I've heard Fai has a twin named Yuui. What episode is he from?
I think I heard Fei Wong say that the real Sakura died. Am I just imagining it?
Do they ever retrieve all of Sakura's feathers?
Is the series over?
Thank you!!