Why did he attribute the warning not to harm Yakov to "the G-d of your father" and not to the G-d of Yakov himself?
Seforno: Because he did not consider Yakov sufficiently worthy of Hashem appearing to him on his own merit, since he had stolen his heart and fled without informing him.
Why did Lavan add the word "Leimor"?
Oznayim la'Torah: Because Hashem told him to inform Yakov of his dream.
Why is Lavan telling Yakov that Hashem told him not to harm him?
Bechor Shor: He shows him that he did foolishly. I have power to harm you. This is why Hashem needed to warn me not to!
Oznayim la'Torah #1: Refer to 31:29:2:1.
Oznayim la'Torah #2: In order to boast that Hashem had appeared to him.
Who was Lavan referring to when he said "Yesh le'Eil Yadi ... La'asos Imachem Ra'ah" (that he has the power to harm them)?
Tosfos ha'Shalem (3, citing R. Efrayim): He could harm Yakov and his slaves. He would not harm his own daughters and grandchildren.
Oznayim la'Torah: He was referrng to all those mentioned in the previus Pasuk - Yakov, his sons and is wives. 1
Oznayim la'Torah: A clear indication that he inytended to destroy everything - as we say in the Hagadah "Bikesh Lavan La'akor es ha'Kol.'