What was Yitzchak thinking when he asked Esav who he was?
Ramban: He thought that he had eaten from the venison of Esav and blessed him, and that this was Yaakov coming for a Berachah, too.
Why did Esav say "Ani Bincha Vechorcha Esav"? Yaakov said in the opposite order, "Anochi Esav Bechorecha" (27:19)?
Refer to 27:19:151:1.
Why did Esav say "Ani Bincha..."? Yaakov (27:19) did not say "Bincha"!
Ha'amek Davar: When Yaakov came, Yitzchak knew that he was his son, and said "Mi Atah Beni," so he did not need to say that he is his son. Yitzchak asked Esav, "Who are you?," so he needed to say "Bincha." 1
This was not so necessary, for initially he said "Avi" (27:31), and now he said "Esav"! (PF)