Just out of curiosity, if a couple is irregularly married (lack of canonical form), but is otherwise free to marry, how do they obtain regularization if they attend an SSPX, Resistance, other independent, or sedevacantist chapel?
I suppose they could always just approach the diocese where they live, and keep quiet about what they do WRT the Mass and sacraments, submitting the necessary paperwork, and making it a done deal. This would be more difficult for sedevacantists --- do they recognize any authority of the institutional Church at all, to do this sort of thing? It seems to me that, in principle, saying there is no pope is not quite the same thing as saying there is no Church. During papal interregnums --- and SV seems just to be such an interregnum writ very large --- all of the Church's acts do not come to a screeching halt. Ecclesiaprivationists would, of course, be in quite a fix.
So what do people do?