If this used UTF-8 instead of a separate code page, it could be made part of the engine itself. As it stands it'd have to be an add-on.
Also, concerning Strife dialogues, there really should be a more versatile way to translate them, aside from recreating their entire content.
The only reason why nothing had been done on that front is that nobody was ever committed enough to do a full translation for another language, especially one with a different alphabet. I see that you seem to be really interested in making this work, so how about joining forces to do it RIGHT? I guess some issues with the font files will have to be resolved but these things should be doable.
I don't know if the FON1 and FON2 formats support more than 256 characters but again, it should be solvable. I actually would deprecate them anyway and instead add the font part of imagetool to the font loader so it can work off the raw images instead of the binary output. And once there, the rules could be simplified to allow skipping unimplemented characters.