I just haven't had time to discuss this fifth opinion. I'll get back to it after I put my kids to bed.
In summary, though, it's not just about my own personal arguments; the fact that there are FOUR other opinions held by well-educated reputable theologians by itself and prima facie indicates that this subject is not as obvious and as straightforward as most sedevacantists would have it be. So, for instance, it's not a unanimous consensus of the Fathers. What's the unanimous consensus of the Fathers is simply the MAJOR of St. Robert Bellarmine's argument, i.e. that a heretic is not a Catholic. But there many other nuances, distinctions, and problems in play here. It's NOT as simple and obvious as most sedevacantists portray it.
And, mind you, that perspective comes from a person (namely, myself) who leans strongly sedevacantist.