Yes, you can install on one machine, move the drive to a different machine, and it should mostly just work (unless they are different architectures and the packages aren’t compatible). I’ve recently moved an old Arch install into a basically new computer and after changing the microcode it just works fine.

These look awesome! I’m curious what your favourite switches are out of the bunch? I’m also interested in a comparison between the Boba U4T vs MMD princess, if you have any thoughts to share!

I doubt it - the bootloader is very different on iPads and I don’t think it would let you boot a different OS