ages:
sakura ans syaoran are confirmed to be 15.
fai and kuro havent been given difinitive ages by CLAMP, but their both in their 20s. some people say that since kuro is closer to tomoyo's age (see lecort arc, what ever vol syao goes into that book) fai is older than kuro.
their skipping around a bit for a few possible reasons:
1 shura arc is darker, and bloody and violent...not something really nice to start the seaon off with
2 start with piffle world so that the CCS fans get drawn in just to see Tomoyo act like tomoyochan from CCS.
3 the fai-centric episode, just aired, would reel in alot of chobits fans just to see Chii, sumomo and Kotoki, (as well since sumomo and kotoki were back in chibi form rather then the oposite like in outo)
at least theyre running the shura arc next. its going to be 4 episdes, which is cool. i hope they do the Country of idols afterwards, before heading off into Lecourt country.