Since Yisrael borrowed the Egyptians' vessels, why did they not return them?
Ohr ha'Chayim: Refer to 3:18:3:1.
Seforno: When Pharaoh attacked Yisrael at the Yam-Suf, Yisrael acquired the borrowed objects as spoils of war. 1
Rashbam: In fact, they did not borrow the Egyptians' vessels at all; they asked for them as gifts. 2
Riva #1 (12:36): Hashem owns all wealth [and He authorized us to keep them].
Riva #2 (12:36): It was proper to keep them to be wages for their work. 3
Seforno: Measure for measure - since the Egyptians came to kill Yisrael and to take their possessions as spoils, Hashem killed them and Yisrael took their possessions as spoils.
Da'as Zekenim, Hadar Zekenim: Seeing as the Torah writes that at their departure, Hashem placed the favor of the people in the eyes of the Egyptians (12:36). Rashbam - And they gave willingly, due to their fear of the Makos.
As the Gemara records in Sanhedrin 91a, in connection with the international tribunal that Alexander the Great set up - where a wise hunchback called Gevihah ben Pesisah put forward that very argument when the Egyptians demanded the return of their Kelim, and won. (cc)
Why did Hashem instruct them to ask specifically for silver and golden clothes (Rashbam) and women's clothes?
Rashbam: In order to dress their sons and daughters respectfully in honor of the forthcoming Yom-Tov. 1
I.e. the day of Matan Torah - Shavuos. See also Ba'al ha'Turim.
What is the meaning of "v'Nitzaltem Es Mitzrayim"?
Rashi (citing Targum Onkelos) and Targum Yonasan: It means that they emptied Egypt 1 (of the articles mentioned in the Pasuk). 2
As the Gemara explains in Berachos (9b) (commenting on the word "va'Yenatzelu" (12:36)) 'They made it like the depths of the sea where there are no fish.' See also Ba'al ha'Turim.
Later at the Yam-Suf, they received even more booty in the form of ornaments (See Rashi to Shemos 15:22).
Why were women commanded to ask from "mi'Garas Beisah," but not from 'mi'Gar Beisah' (i.e. a male Mitzri living in her house)?
R. Yehudah ha'Chasid: No Yisrael would allow a Mitzri in his house, 1 lest he be secluded with his wife or rape her, or lest she desire him, and this will spoil the [Yisrael's] children from his wife. One can have a Mitzris in his house. His wife will guard against seclusion, and he can guard himself from desiring her.
This is also the intent of Moshav Zekenim, but there is a printing mistake.