2/ But there can exist a "possibility" for a manuscript to be translated. What do you make of {ghItlhvam mughlu'meH DuH} ? 

>> As in: ghItlhvam mughlu'meH DuH tu'lu'be' = There is no possibility to translate this manuscript / it is impossible to translate this manuscript

>> of course a simpler (safer) way to say it could be {ghItlhvam mughlaH pagh} = no one can translate this manuscript

This isn't an example of mughlu'meH DuH; this is an example of mughlu'meH tu'lu'be'. The DuH just happens to be in the way.

Look, just drop the -lu' and everybody is happy. ghItlhvam [mughmeH DuH] tu'lu'be'. The bracketed phrase is a purpose clause with a head noun meaning possibility for translating. It avoids the negative purpose clause problem; it avoids arguments about objects on purpose clauses.

Better yet, just say ghItlhvam mughlaHbe' vay' and avoid the whole mess. Choose a more appropriate subject for a given situation. Add laH ghajbe' afterward if you like. There's no reason to insist on mirroring English syntax.

-- 
SuStel
http://trimboli.name