I'm not even sure what limitations I'm up against. :/
For example, I've found a font that supports Cyrillic and Latin. However, when I view the ttf, even though I can only see Latin characters in the window, I can set Cyrillic inside c2 directly.
So, my first confusion is that I don't appear to be able to inspect the Cyrillic inside the ttf file.
Then, when I install the same font as a web font in c2, the Cyrillic characters transform to the system default font. I've no idea if this is a limitation, bug, or something that just could be sorted by a css input.
As part of the text object font setting there's a drop down list of supported scripts. I thought that these could be automatically selected according to the Unicode character being input, but this doesn't seem to be the case....