Joe, what makes you so sure that Katzenelson is not the author and do you know more how that information originated? The last time I have read this (wrong?) information was in a recent book, Jizchak Katzenelson, Dos lied vunem ojsgehargetn jidischn volk.
I've also read that 'Dona, dona' was in the original 'Adonai, Adonai', meaning 'my God, my God', but that might be wrong too.

Wolfgang