I am not a follower of the "Resistance", nor of the SSPX or sedevacantism, for that matter. But I am a Dutch speaking Belgian, and Eric Jacqmin is certainly an open sedevacantist, defending it on his website "SCATURREX". On that website he considers sedevacantist bishops such as Geert Stuyver and Donald Sanborn to be legitimate, and also those Ukrainian bishops who erected their own Patriarchate under a so-called Patriarch Elias.
It kind of surprises me that people are unaware of this here, so it seems to me that the "resistants" have significant problems with communication.
Jacqmin rejects Williamson, calling him a practical heretic because he refuses to create his own church-structure.
It does not surprise me that sedevacantists would want to ally with the post-SSPX splintergroups, because they truly are like a duplicate of the sedevacantist world, with all its disorder and anarchy.