Why does it mention Esav's wives before his sons, and regarding Yaakov (31:17), the reverse?
Refer to 31:17:1:1, and 31:17:1.1:1.
Why does the Torah refer to Esav's six family members as "Nafshos Beiso" (in the plural), and Yaakov's seventy family members as "Nefesh" (46:26)?
Rashi (to 46:26): Because the latter worshipped only one G-d, whereas the former worshipped many gods.
Why did Esav leave Eretz Kena'an?
Rashi #1 and Ramban (both to 36:7): Because there was not sufficient pasture land 1 for both Esav and Yaakov.
Rashi #2: In order to escape the decree against Yitzchak ,"Ki Ger Yih'yeh Zar'acha b'Eretz Lo Lahem" (15:13). 2
Rashbam: Because Yaakov had bought the birthright from him, and the land of his fathers therefore belonged to Yaakov.
Rashi #3: He was embarrassed by the fact that he had sold the birthright to Yaakov. 3
Targum Yonasan: He was afraid of his brother Yaakov. 4
Moshav Zekenim (to Bereishis 35:29): He knew that Birkas Avraham was given to Yaakov, and Yaakov would inherit Eretz Kena'an.
Ramban: - in Chevron; and since he had to leave Chevron, he decided to move to another country. Rashi - His choice of Har Se'ir was random; it happened to be the first country that he arrived at. Gur Aryeh explains - If Esav knew where he was heading, the verse could have written, 'to dwell in another land.'
He decided that neither Eretz Kena'an nor the 'Shetar-Chov' that preceded it were for him.
See also Oznayim la'Torah, DH 'Vayelech el Eretz' for other reasons as to why he was embarrassed to remain in the vicinity of Yaakov and as to why he deliberately left Eretz Kena'an for 'a more convenient' location.
See Na'ar Yonasan.
When did Esav leave Eretz Kena'an?
Ramban #1: While Yaakov was still in Charan, Esav moved to Har Se'ir with his 400 warriors, to rule over the princes of the Chori, leaving his family in Chevron.
Ramban #2: Initially, he owned only a small area in the plains of Har Se'ir - which is why the Torah wrote "Artzah Se'ir Sedeh Edom" (32:4). It was only after Yaakov returned to Chevron that he moved with his entire family to the land of Se'ir.
Moshav Zekenim #1: This was before Yaakov went to Charan, 1 for Esav was already in Se'ir when Yaakov returned, 2 and we do not find that he returned to Eretz Kena'an.
Moshav Zekenim #2: We can say that it was after Yitzchak died, for Esav returned to bury him. 3
Oznayim la'Torah: Refer to 32:4:6:2.
Moshav Zekenim: Verse 36:7 says that the brothers had too much property to live together! Yaakov was 63 when he left; perhaps he had great wealth already. (It seems that Esav heard Yitzchak tell Yaakov to go to Charan right after he took the Berachos! Perhaps he thought that he will marry, and return very soon. This requires investigation. (PF))
The Ramban proved this from 32:4. On his return to Eretz Yisrael, Yaakov sent messengers to Esav in Se'ir. You cannot say that he left while Yaakov was away, for 36:7 says that he left because the brothers had too much property to live together! (PF)
I.e. initially Esav alone was in Se'ir. After Yitzchak died, he took his family to Se'ir. (PF)
What does it mean, "va'Yelech El Eretz"?
Ramban: It is understood that he went to Se'ir, like it says above (32:4) that he was in Se'ir. Sometimes a verse omits the prefix 'Hei. 1 '
Ha'amek Davar: Before he settled in Se'ir, he distanced from Chevron and went to an unnamed place near Se'ir. Ultimately, he settled in Har Se'ir.
Rashi: He went to a land - i.e. to live in some [as-yet undetermined] place, where he would see fit.
Ramban: E.g. "Beis Melech" (Melachim I 16:18) in place of Beis ha'Melech, and other examples.
