I have a first draft done of a system, based on Soeker’s approach, which constructs Microsoft Word initialization files with diacriticked fonts prepared from a specification file.
Sounds like you are trying to use shareware fonts. The ones I downloaded in my initial spate of enthusiasm a couple of years ago were usually missing a lot of the diacriticked characters such as those you mention.
I’ve been googling for the languages individually (for instance the link below has the sorting order for Czech), but for some languages, I can’t seem to find it at all (Romanian, for example). That’s not to say I can’t find their alphabet, but some languages (as Czech) sort some of the diacriticked letters as separate letters and others a variants of the base letter. This kind of info is hard to find.