I see one big show stopper in your thinking: game saves (campaign saves). There is a multitude of campaign data written into save games (it's evident from CTDs that happen when user tries to load old save game on new campaign data - aka OHII). If you look at the save games in a hex editor the data is not easily discernable. You would first have to decode the save game files to learn what they contain then you would know what you are up against

As far as the campaign files being able to 'read' meta data, good luck. I haven't seen anything in the SH5.exe or any of the ACT files that looks anything like it's trying to read meta data. It's pretty evident from viewing them in disassemblers that they have a strict pattern of data format that they look for. This is also readily apparent when one tries to manually edit a .mis file and makes a typo or something and the game CTDs.