A Yerushalmi and a non-Yerushalmi read the Megillah on different days. May either of these people read the Megillah for the other on whatever day the listener needs to hear Megillah? Or does it need to be read by someone who is obligated in the mitzvah on that specific day?

Would one fulfill his listening obligation bedi'eved if this was done?

Residents of a walled city and unwalled cities celebrate Purim on different days. May either of these people read the Megillah for the other on whatever day the listener needs to hear Megillah? Or does it need to be read by someone who is obligated in the mitzvah on that specific day?

Would one fulfill his listening obligation bedi'eved if this was done?