I have noticed that the fukuin name Shannon and her real name Sayo have the same initial kanji. If we speculate that the same thing is done for any fukuin name, how many male japanese names can have that particular kanji in "Kanon"?
I wonder if anyone tried to figure it out already. After a brief research i found out that there was a japanese actor named Kato Yoshi
source and the Kanji of the name is the same as the one in Kanon.
So maybe Kanon's real name is Yoshi? Any other possibility?
EDIT: found another one, even more probable:
http://en.wikipedia.org/wiki/Yoshitaka_Amano