Why does it say "va'Yikach Es Leah"?
Ohr ha'Chayim: He forced her, or needed to persuade her. She did not want to trick Yaakov!
Why does it say "va'Yavei Osah"?
Ohr ha'Chayim: He did not give her (like is normally done) to his messengers or to Yaakov's, to minimize the time for Yaakov to recognize her.
Regarding Rachel (29:28), it says that he gave her to Yaakov "l'Ishah." Why does it not say so here?
Ha'amek Davar: Leah was not his wife until he knew that it was her, and consented.