Why did Yaakov repeat the names of all those who were buried in the Me'aras ha'Machpelah?
Ramban: He stressed the importance of the location in order to encourage them to fulfill his request and bury him with Zerizus (alacrity). 1
Ohr ha'Chayim: The initial owner was Efron. After they buried Avraham and Sarah there, [the influence of] the initial owner was decreased, and it stood in the possession of Avraham's heirs, Yitzchak and Yishmael. It mentions that they buried Yitzchak to exclude Yishmael; it is only in the Reshus of Yitzchak's heirs, Yaakov and Esav. Refer to 49:31:3:1.
Malbim: This shows that he acquired it for a cemetery. It mentions Yitzchak's burial to refute any claims of Bnei Yishmael. Also refer to 49:31:3:1.
Ha'amek Davar: This is a third reason why Yaakov wants to be buried there. A person wants to be buried with his fathers!
In spite of all the hurdles that they would encounter.
Why did he say "they buried Yitzchak," seeing as he personally had buried him?
Ramban #1: Because Esav was also involved in his father's burial, and he did not want to mention him at this point.
Ramban #2: Because he would have to add 'and there they buried Rivkah his wife;' 1 so he combined them and wrote briefly "there they buried Yitzchak and Rivkah his wife."
Ramban: At whose burial Yaakov had not been present.
Why did Yaakov find it necessary to point out that he buried Leah there?
Ramban, Malbim: He was preempting Esav, who, he suspected, would claim the right to be buried there. 1 Ohr ha'Chayim - After they buried Yitzchak there, it was in the Reshus of Yitzchak's heirs, Yaakov and Esav. It mentions Leah's burial to exclude Esav; Chazal (Sotah 13a) expounded that Yaakov bought Esav's share.
Ha'amek Davar: This is another reason why Yaakov wants to be buried there. A person wants to be buried with those who served him in his lifetime, like we find regarding Rebbi (Kesuvos 103a).