“And are the new Roshei Yeshivos yet on the Moetzei Gedolei HaTorah?”
What I had actually posted was: One does not inherit an open slot on the Moetzes Gedolei HaTorah; one earns it.
Anyway, Rabbi Reuven Schepansky (son-in-law of Rav Shmuel Berenbaum zt”l) and Rabbi Herschel Zolty (son-in-law of Rav Shraga Moshe Kalmanowitz zt”l) are also Roshei Yeshiva of Mir.