Why was Yaakov only concerned that Lavan would steal his daughters (Yaakov's wives), and not anything else?
Seforno: As a matter of fact, he was worried that he would hold back his daughters, as an excuse to steal his (Yaakov's) sons and his money, 1 with the help of his townspeople.
Tosfos ha'Shalem (3, citing R. Efrayim): Money can be replaced, but nothing can be in place of your daughters.
Malbim: Lavan claimed that Yaakov did not work for his daughters, so he may not take them wherever he wants (refer to 30:28:151:2). Yaakov said that he worked for them, and he may take them.
As Lavan himself intimated (See 31:43).
Why did Yaakov first answer Lavan's accusation that he led away his daughters like captives?
Rashi and Rashbam: In keeping with the Mishnah in Pirkei Avos (5:7), that a wise person answers the questions that are put to him in the order that they are asked.
Did Yaakov admit that he took Lavan's daughters like captives?
Ha'amek Davar: Yaakov did not want to say that his wives encouraged him to flee, lest Lavan have gripes against them. He explained why he was forced to flee with them, 1 lest Lavan steal them.
Ha'amek Davar: Since he justified why he needed to flee covertly, this refuted the basis of Lavan's claim that he stole from Lavan.