[Cajundaddy]

Newport Beach is a family favorite. Rent bikes and cruise the boardwalk, the water should still be warm and the waves are manageable unless you hit the Wedge. A train ride down the coast to San Clemente Beach might be fun.

Long Beach Aquarium is hard to beat and reasonably close to Anaheim.

Spending a day at Griffith Park can be pretty great including nice easy trails on the N side and the observatory is a cool visit.

I would personally avoid downtown LA or anywhere that is filled with homeless camps. It's a 3rd world country there.

Edit: I don't know how much time you have spent in SoCal but traffic can be a vacation buster if not carefully planned to avoid the biggest jams. We always use an app like Waze to plan and navigate around the worst of it. Sometimes traveling 30 miles can take up to 3 hours if you are not prepared. Generally, heading towards LA/Long Beach in the AM and away from LA in the PM presents the worst snarls. Other than that, the weather should be great.