Personally, I think all the focus on Kohane is to build up to the reveal that she's clone!Sakura's soul. (Though, if true, what does that make Watanuki? But then, I also think that the petal clone!Syaoran grabbed when she...uhm...disnitegrated was a piece of her soul that became his soul.)

And this is very true about Himawari. At least Doumeki has been lurking about in the background and chatting with Yuuko.