1)
What is the meaning of "l'Machlekos ha'Sho'arim"?
1.
'Rashi': They do not guard based on a rotation. Rather, they were divided according to the gates. Later they cast a lottery to decide who will be on each gate.
2)
Is Meshelemyah ben Korei the same as Shalum ben Korei (9:19)?
1.
'Rashi': Yes. Malbim - Shalum was over Shomerei ha'Sipim, and his son Zecharyah guarded Pesach Ohel Mo'ed (9:19-21).
