What did Yakov mean when he said "Ki Mal'u Yamai"?
Rashi #1: He meant that the time period that his mother had in mind 1 had elapsed.
Rashi #2: He was already eighty-four, and if he did not begin raising the twelve tribes now, when would he do so?
Targum Unk'lus, Targum Yonasan, Ramban #1 and Rashbam: He was simply referring to the termination of the seven years that he had stipulated that he would work for Rachel. 2
Ramban #2: This took place towards the end of the seven-year period, and Yakov was asking Lavan to consider as if they had actually terminated, and to allow him to marry Rachel already then. 3 (Refer to 29:21:2:3.)
Why did Yakov say "v'Avo'ah Eleha" (I will have Bi'ah with her)?
Rashi: Precisely because he was so keen to begin performing this great Mitzvah, he spoke so bluntly, using words that even the most immodest person would not use. Refer to 29:21:2:5.
Seforno: What he meant was that not only should the betrothal take place now, but also the wedding, in order to have children.
Ramban: I will marry Rachel now, and continue to work until the seven-years are complete. 1
Tosfos ha'Shalem (8): Bnei Noach do not have Kidushin. Marriage is only through Bi'ah. Also, he did not have any money for Kidushin. He could be Mekadesh her only through Bi'ah. 2
Pri Tzadik (Pinchas 4): Yakov reached the level of Adam ha'Rishon before the sin. Adam was not ashamed to be naked, for he had no thoughts of physical pleasure. 3
Ohr ha'Chayim #1: Lavan owed him for his Avodah; a loan does not make Kidushin. The Kidushin will be through Bi'ah.
Ohr ha'Chayim #2: Yakov held like the Ramban, that one can acquire slaves and land via a loan, even if the money is not intact. She is already my wife; give her to me, so I will have Bi'ah with her like any man with his wife, but not to make Kidushin now.
Ha'Emek Davar: Now she is not a minor, nor weak (refer to 29:19:1:5), so I can have Bi'ah with her.
This explains Lavan's statement (in Pasuk 27) "Malei Shavu'a Zos ... ", i.e. complete the seven-years that you had almost finished working for Leah (as it turned out).
If there were witnesses for Kidushin, he could make a Kidushin document! And some say that the husband's signature suffices! Perhaps he holds that documents do not apply to Bnei Noach. (PF)
Why did he call her "Ishti"?
Refer to 29:21:2:7.
Malbim: She is already my wife through designation for me. He is no less than Bnei Noach; once a woman is called on Ploni's name, she is his wife, and people are liable for her (for Eshes Chavero).