Just read entirety of Holic in one day...Now I'm up to speed! I should've been reading this all along! As to the poll question, I don't see there being another option but that they're canon. That, to me, is like asking if Hideki and Chi are canon halfway through the series...No they haven't confessed or anything, but the story is quite obviously about them and their relationship. It is different that TRC, where Kuro and Fai are just side characters, the main story is getting Saku's feathers back, and their romance is just a side bonus; to me, Wata/Dou IS the story in Holic..anyone else agree/disagree?
Oh, as to Piffle Princess, it's in CCS too!