pffffft ... none of them are sedeplenists. To be a sedeplenist you have to believe in the legitimacy of the pope with the certainty of faith. +Lefebvre, +Williamson, and +Tissier have all expressed doubts at one time another about their legitimacy. No Catholic could do that of a true pope any more than he can question the truth of any defined dogma.
You put your ignorance on display yet again. Sedeprivationism militates AGAINST conclavism.
Father Chazal is unquestionably a sedeprivationist ... whether or not he'd lay claim to the term. He is NOT R&R. Standard run-of-the-mill R&R holds that some V2 papal teaching is legitimate and must be accepted ... if it's traditional and it's true. +Chazal claims that all of it is null and void due to the heresy of the occupants of the office, i.e. that they are completely deprived of any formal authority. Thus, sedeprivationist.
You are failing to distinguish between the belief that a pope can be judged a formal heretic and how it occurs, and doubt about the validity of a pope. These so called doubts of +Williamson,+Lefebvre, and +Tissier are not at all a doubt about the validity of the conciliar popes. If they had a doubt, they would be non una cum like all the others who at the very least concluded such. So, what it is is a doubt or question about whether a pope can become a formal heretic, and how that occurs. I personally don't believe a pope can ever become a formal heretic. And, neither do I believe that a perfect council can judge a pope a formal heretic. But, they did not/have not come to that conclusion. Hence, the discussion you are abusing. But make no mistake, it is not a doubt about the validity of the popes. And, fuss about legitimacy is child's talk.
The catholic world is not the popes diocese. Rome is the popes diocese. The pope gives authority to bishops. But, such bishop(s) does not then become only a mere messenger of the pope. Bishops have true authority. There are checks and balances among bishops, pope included. St. Peter keeps the bishops in check. And, a bishop in the spirit of st paul keeps the church in check, pope included. Just as the office of the papacy endures until the end of time. The spirit of st paul endures among the bishops until the end. The pope indeed does have supreme power. But, he only has the keys. St. paul has the sword. Both are needed in the church. So, legitimacy is child's talk. The church can function one might even say normally with a heretical pope. That is not to say there is a place for vatican 2 in the church. There is not. Thanks to +Lefebvre. Thanks to +Williamson. So on and so forth. R&R is the true traditional position. And, it is a sedeplenist position.
So, enough of you promoting papal suzerainty and papal impeccability like all the dogmatic sedevacantists do. They are in error. You are in error.