Why does the Torah list the sons of Amram, Yitzhar and Uziel, but not those of their brother Chevron? He had sons, for it says (Bamidbar 3:27) "u'Mishpachas ha'Chevroni"!
Moshav Zekenim: Amram, Yitzhar and Uziel, the Torah mentions children from theim 1 , but not from Chevron. Likewise, it does not name here the sons of Isamar (Rashbam) or Moshe (Hadar Zekenim), or the grandsons of Gershon and Merari (Da'as Zekenim, verse 21).
Da'as Zekenim (verse 21): He did not have sons. 2
Rashbam: E.g. Korach from Yitzhar, Misha'el and Eltzafan from Uzi'el. Even though the sons of Korach are named only here, they are mentioned elsewhere (u'Vnei Korach Lo Mesu - Bamidbar 26:11).
What does "Zos" then come to preclude?
Ramban: "Zos" precludes Chatas ha'Of from Kibus Begadim.
Why does the Torah change the order of Korbanos (Olah, Minchah, Chatas, Asham, Shelamim) from the order in Parshas Vayikra (Olah Shelamim, Minchah, Chatas, Asham)?
Ramban, Moshav Zekenim: Whereas in Vayikra, the Torah began with the Nedavah and went on to the Korbanos Chovah, here it begins with Kodshei Kodshim and goes on to Kodshim Kalim. 1
Ramban: This in turn, is because, to some extent, Kodshei Kodshim all share the same law (See Pasuk 10). Moshav Zekenim asks, why was Minchah taught between Olah and Chatas?
Why did the Torah fix the same location for the Shechitah of a Chatas as that of an Olah?
Rashi (in Sidur Rashi), Moshav Zekenim, from Yerushalmi Yevamos 8:3: Because of Kavod ha'Beriyos - If the Korban Chatas had its own specific location, everyone would know that whoever appears there with his Korban sinned. 1 But now that it shares a location with an Olah, they will not know that it is not an Olah 2 that he is bringing.
Ramban: To incorporate all Chata'os in the law of Tzafon, even Chata'os ha'Tzibur and Chata'os ha'Penimiyos. 3
Kli Yakar: According to the opinion that Olah atones for sinful thoughts, both are in the north, for "mi'Tzafon Tipasach ha'Ra'ah" (Yirmeyah 1:14). According to the opinion that Olah is a Nedavah, after one repents and brings a Chatas, it is acceptable like an Olah, which is the choicest Korban.
Moshav Zekenim: Rav Hai Gaon explained that in the Mikdash, when people bow, there is space between them (Avos 5:5), in order that one will not hear another confess.
Kli Yakar: This is difficult. One can see that it is not Kalil like an Olah, and that it is a female, unlike an Olah!.
Seeing as in Parshas Vayikra, it only mentioned Tzafon in connection with the Chatas Nasi and the ChatasYachid (Ramban).
Why does the Torah add "Kodesh Kodashim hi"?
Ramban: To incorporate the Zivchei Shalmei Tzibur (on Shavu'os) 1 in the law of Tzibur.
The only Korban Shelamim to be brought by the Tzibur and the only Korban Shelamim to fall under the category of Kodesh Kodashim.
Why does the Torah tell how long Kehas lived?
Rashi: It teaches that the 400 years decreed at Bris Bein ha'Besarim were not all in Egypt, for Kehas descended to Egypt, and if we add all his years and Amram's and 80 of Moshe, we do not reach 400. Rather, they are counted from Yitzchak's birth.