I've been too busy to spend much time on this, but I did play with the Kinetis SDK. I can get the LED to light using a project build for KL43Z, but only when the SWD debugger is physically connected. I think this has to do with the fact that I've built my "Hello World" in debug mode, and the micro is hanging on an unanswered semihosting breakpoint call. I'll dig into this in the next couple of weeks.
Also committed the KiCAD project complete with gerbers I used to make boards and stencils on Github: https://github.com/pokey9000/tbd