Does Fr. Kramer now subscribe to the sedevacantist delusion that sedevacantists alone have comprised the visible Church since 1958? If so, at this point, he may be doubting his own priesthood.
Regarding Fr. Kramer, you mentioned he was ordained in '76. Do you know anything else about him, e.g. when and where was he born, where did his study, by whom was he ordained, how does he pay for the bread on his table, etc.? Have read his book, "Devil's Final Battle" and watched a few of his Youtube videos, but beyond that, know very little about him, except that he was involved with the late Fr. Gruner and the Fatima Crusade.
Fr. Gruner: The "Sedevacantist" Theory is False
Christopher A. Ferrara: Defending the Papacy Opposing the Sedevacantist Enterprise
I also have read the Devil's Final Battle but do not have answers to your other questions. But I need to clarify: Because of Francis' heretical Evangelli Gaudium, Fr. Kramer has declared Francis to longer be a legitimate pope. Fr. Kramer, however, recognizes Pope Benedict to the current, valid Vicar of Christ.