Who are the Kemarim?
Radak: They are those who serve in front of Ba'al. Tzefanyah 1:4 mentions Kemarim and Kohanim! Both of them serve idolatry. Kemarim wear black; therefore they are called Kemarim, like "Orenu k'Sanur Nichmeru" (Eichah 5:10). [Evil] Malchei Yehudah had appointed these Kemarim. Yoshiyah eradicated the idolatry, and stopped them from serving, and caused them to improve their ways.
Malbim: They are Kelim for offering to idolatry.
What is the meaning of "va'Yakter ba'Bamos"?
Rashi: Those who offered on Bamos in cities of Yehudah.
Radak: Every king offered (Targum Yonasan - incense) on a Bamah.
What is the meaning of "u'Mesibei Yerushalayim"?
Rashi: It is like uv'Mesibei (and in places around Yerushalayim).
