How is it possible for a Jew to have no heirs (seeing as all Jews are related via Ya'akov Avinu and his descendents)?
Rashi: The Pasuk is referring to a Ger who has no heirs. 1
Seeing as a Ger who converts is like a newborn baby (Yevamos, 22a).
What are the implications of the phrase "ha'Asham ha'Mushav la'Hashem la'Kohen" mean?
Rashi and Seforno: It implies that, if the owner of the money is no longer alive, then the money goes to his Master (Hashem), who passes it on to the Kohen.
And what is the "Eil ha'Kipurim"?