Welp. I don't know what I'm talking about. But at least for key remapping, I use `hidutil`. For example, to remap right ctrl to fn:

  hidutil property --set '
    {
      "UserKeyMapping": [
        {
          "HIDKeyboardModifierMappingSrc": 0x7000000E4,
          "HIDKeyboardModifierMappingDst": 0xFF00000003
        }
      ]
    }
  '

To make it stick through reboots, you can run it in a launch agent. Posted my notes and plist file here: https://gist.github.com/andelink/9df452c8cafb6790f196277705c...

For window tiling, can't say I've ever looked into it.