The two librarians are Sai and Kaede from Angelic Layer. But you're right too, Yuki-chan, Kaede crossed over into Chobits... I think she was Minoru's older sister. But she was already dead in Chobits. T_T; Of any of the crossovers, I was happy to see those two! They were my favorites in AL, especially Sai. ^^
Heh, I LOVED their faces in the end. ^___^ Kuro-chan looks so proud of his student, and I bet he's looking forward to being a thief. I imagine Fai is too, ne, Sakaki-chan? ^______^
(Just an aside, I added a note to the translation about two of the names. "Biblio", the town, which is "book" in Latin, and "Hund" which is dog in German. They both make sense so I think I got them right. How would I survive without Google? ^^;; Although I find it random that CLAMP can't seem to stick with a nationality for this country. Because then there's "Lecourt", that sounds French (if that's even the right spelling). And of course Harry Potter=British.
Whatever. ^^;;; )