Why was Yakov only concerned that Lavan would steal his daughters (Yakov'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 (Yakov'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 Yakov did not work for his daughters, so he may not take them wherever he wants (refer to 30:28:151:2). Yakov said that he worked for them, and he may take them.
As Lavan himself intimated (See Pasuk 43).
Why did Yakov 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 Yakov admit that he took Lavan's daughters like captives?
Ha'Emek Davar: Yakov 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'Emek Davar: Since he justified why he needed to flee covertly, this refuted the basis of Lavan's claim that he stole from Lavan.