Why am I skeptical that there has been any formal declaration that Marcel the miscreant is "Venerable?" Maybe because no one wh died excommunicated in schism has been so designated. I will give you the benefit of the doubt for now but, since the acts of the Holy See are published, perhaps you will provide an authoritative link (not from the schism, of course, but) from the Vatican itself in an official publication of the papacy. I've got to believe that being the "devil's advocate" on such a cause for sainthood would be a slam dunk.
When did the Holy Ghost designate the schism as His spokesfolks? I missed that one too. This sounds a little bit like: This is the House that Jack Built!
You doubt the Pope has called "venerable" one who has died excommunicated? Gosh, you are such a Big Blue Meanie