The quotes from the sefarim above are very weak, they say that a tzaddik has a nitzutz of moshiach etc.
And the whole idea, that each Chasiddus can believe that their Rebbe is Moshiach (even though there's only 1 Moshiach [ben david]), reminds me of when Cee Lo Green's changed the words of 'Imagine' from "and no religion too", to "and all religions true".