As far as the Zantetsuken, that's as good a theory as any, but Odin Was not its origenal weilder just possibly the most compatable with it. (Odin could have been a simmilar person to Zantetsuken's creator when he was mortal)

In regards to the Jazalan theory, there's no proof but no disproof either. We know to little about the kid to make any theories in his reguard.