Father Chazal does raise some interesting points with regard to jurisdiction.
Can a Pope who has lost teaching authority still excercize jurisdiction (albeit illicitly)?
Key to sedeprivationism is this notion that a material pope can in fact appoint Cardinals, who can in turn elect another Pope (who could be a full formal pope at that time ... if he doesn't have the impediment to be the Pope). So at the very least the power of designation must remain. And that is a key aspect of jurisdiction.
So, just as these Cardinals appointed by a material Pope can elect a Pope who's a full formal+material Pope, so I hold that a material pope can appoint bishops, who, if they do not have any impediments to the formal exercise of office, can formally exercise the prerogatives of their office. With this the whole "ecclesiavacantist" problem of the straight sedevacantists evaporates. Jurisdiction continues in the Church. This is important, nay, crucial, as straight sedevacantism holds that (non-supplied) jurisdiction has ceased in the Church.