Thanks, Shticky.
As for your lots question, according to footnote #1 on page 178 of “Let My Nation Live” by R. Yosef Deutsch: “Sarah’s death was a zechus. After she died, the torch of the Imahos, the Matriarchs, was passed to Rivka. Also, Sarah’s death occurred upon finding out about the Akeidah. The merit of Cheshvan was the Akeidah itself; see Iyun Yaakov to Megillah 13B.)
Maybe you could also make a case for Moshe’s death being more of a national tragedy, as we technically were not yet a nation at the time of Sarah Imeinu’s passing?