Re: I cannot revert back to fullscreen
Neither of the 3 CFG files has a setting that would trigger a windowed display.
To be honest, I have never heard of a resolution like you are running so I am tending to think that the game simply can't handle it (eg it simply doesn't stretch that far), considering that the game's default size is 1024*736.
Please try and set the game resolution (via the game's video option) for battle and campaign to 1920*1080 (my resolution - your present setting is 1280*1024 which may be too small to expand to your desktop resolution) and see what happens. I would suggest to use Thera to test as it actually has a configuration that actively disables windowed mode.
Regarding editor - if you haven't had anything weird happening when editing files like the EDU then your editor should be fine.
Note: I am fishing in the dark as I have not come across a resolution like yours.