Anyuser, where is there justification for saying that someone is, will be, may be, moshiach can be based on a hergesh.
The entire hergesh thing in cases like this is “I want, therefore it is.” There is NO place in Yiddishkeit for this, and it is what leads to apikorsus.
I know of one case of hergesh in halocho, and it is tomei, vd”l.