If you're interested in family law, I don't think the overall prestige of your school is as much of an issue than if you were intent on some corporate BigLaw job after school. Given that you know what your specialty is going to be, and Whittier has a great reputation for that specialty, I (if I were in your position) would choose it over SW.
Certainly apply to both though. You'll have plenty of time to decide later. You'll probably have a better chance of getting scholarship $ to Whittier, and if that bears out to be the case...more reason to go there instead.