OK so I've come up with casual outfits for Locke and Rowan, there's not as much variety as I'd hoped for, but it's still cool.
For Locke, I attempted to create a look that vaguely said, "I threw this stuff on," just like a surfer might. Too bad they don't have shorts, flip-flops, and a Hawaiian shirt. I think my attempt at jeans turned out well.
For Rowan I went with the Vulcan-style robes, though with more earth/forest-tone colors, hopefully reflecting her First Nations background. Again, more variety would have been nice.
I may try to be more clever with this later. I just wanted to get it out.