Towards where do they bow?
Radak: They bow towards Sha'ar ha'Heichal.
Why will they leave in the opposite side of where they entered?
Rashi: They are commanded to be seen in the Azarah well (go from one side to the other).
Will they enter only via the northern and southern gates?
Radak: Yes. During the Mo'adim they will not enter via the eastern gate, only via the northern and southern gates, in order to traverse the entire Azarah.
Malbim: Yes. This teaches that they may not enter the eastern gate even though it is open on Shabbos. They will bow "Pesach ha'Sha'ar" (3), but they may not enter.
It is written Yetze'u, and we pronounce it Yetzei?
Radak: The plural applies to the nation; we pronounce Yetzei for each individual, like it says "veha'Ba".
