Exceptions for Mitzvat Yishuv Eretz Yisrael

Q: Concerning the obligation to live in Israel, are there exceptions for Rabbis serving Diaspora communities?
A: Yes, temporarily.
Q: Chazanim serving Diaspora communities?
A: ibid.
Q: People who help Diaspora Jews make Aliya (e.g. Jewish Agency personnel)?
A: ibid.
Q: People who do important work for the State of Israel (e.g. diplomats)?
A: ibid.
Q: If someone is exempted, are his wife and younger children also exempted so that they can live with him?
A: Yes. This is all called to the sake of a Mitzvah for which it is permitted temporarily. Tosafot on Avodah Zarah 13a.