DCA (Disney's California Adventure) has a nice selection of thrill rides (Tower of Terror, Radiator Springs, Screamin', Soarin', Grizzly River Rapids, and Goofy's Sky School), plus some other attractions (TSMM, Mater's Junkyard Jamboree, etc.).
Disneyland also has a fair number of thrill rides (Star Tours, Space, Matterhorn, Big Thunder, Splash, and Indy). So I think either park would be fine for the 7 year old if she's into thrill rides.
For the younger child, it's worth noting that DL doesn't have a lot of the Frozen stuff. The Anna & Elsa meet & greet, Olaf m&g, and Frozen Sing Along are all in DCA. DL does have a comic re-telling of Frozen at Fantasy Faire (FPs required) and there is the A&E pre-Soundsational parade float, but no chance to meet A&E. That being said, I would still for Disneyland on the day when everyone is going into the parks.