I see the mashichist position as kfira or bordering kfira.
We have to believe in the 13 ikarim, one of which is bee’as haMoschiach. Now if somebody would say that Bee’as haMoschiach means eating a pickle, and therefore if you simply believe in eating pickles you have fulfilled this ikar, than he would be promoting kfira, because through this, people would no longer believe in the true meaning of bee’as haMoschiach.
Now to say that believing in bee’as haMoschiach means to believe that a person who died in 1994 is really alive, and that fictitious being is Moschiach , means that they don’t believe in the ikar by it’s true meaning, but only by it’s nonsensical meaning. So that makes them kofrim in bee’as haMoschiach.