They also have one of the lowest cost options which uses glass bottles. I’ve been incredibly happy with the Logan. Even if it’s not as pretty as something from aarke.

Isn’t it typically just kernel sources that would need to be released under GPL? A custom kernel is typically a few steps later in bringing up a custom rom for a device. The existing build is probably enough to try and get twrp running if you can get the bootloader unlocked.

Edit: All the same, very noble. Best of luck getting the sources, and making something useful of them.