You are correct. There are no non-stops on SWA from SEA to any southern California airports.
Southwest Route Map
However, just a random search on a Tuesday in Sept did turn up some options that are still pretty fast and don't involve a plane change. Like SEA-LGB 10:15am- 2:25pm for $76. There's a 5am flight that's direct (no plane change) and only $52...
It's more of a I hate flying thing. I get pretty panicky and normally take a bit of medication. This time I'm traveling with two kids and have to be the responsible one since my husband won't be there to help. The take off and landing are my worst part so I need to minimize it. Thank you so much for looking though!! I appreciate that.