You have a misconception about *self* publishing. No editors except self or self paid for ones. Kindle, Lulu, etc generally take the pile of characters from the self publishing author and pump them straight out. Layout is also handled by the same said *self* author/publisher.
If I'm providing an ePub, fully formatted and standards compliant or a PDF, fully formatted with print requirements, why would I expect them to *deny* the publishing of said document based on permitted languages?
Did it ever occur to you that the reason so many indiginous languages are in danger of extinction are the true non-technical restrictions in trying to use languages that aren't mainstream to some degree?
I mean think about this. If Apple supports Cherokee. Windows supports Cherokee. Linux supports Cherokee. Why should it be so difficult to publish pure Cherokee texts if all the technical and editing issues are being handled by the author/publisher before ePub/PDF submission?