xmacs should not require Canna (at least not in the international version of RH).
Fixed in xemacs 21.1.12-15
Beta3 requires Canna-libs and Wnn6-SDK.
Well, it was out for a while, and at the time it wasn't intended. It's back now, and that's not going to change, as this is needed for integrated Japanese support - note that the Canna/FreeWnn-packages have been changed, so you only get the libs now, not the servers.