If we wanted to specifically express the "many others", i think it
would be better to just write {latlh law'}. In this construction the
meaning remains the same, without "tiring" the reader by making him
read two "plurals" in a row.

I think you're really just reacting to the fact that the plural suffix is optional. I sometimes point out where plural suffixes can be dropped for stylistic reasons, but using the plural suffix is not so much redundant as explicit. I too would probably say latlh law' instead of latlhpu' law' most of the time, but I would only call this out where I feel a stylistic improvement could be made. But I disagree that latlhpu' law' can be reduced to latlhpu' without changing the meaning. Sometimes the presence or lack of law' may not make a difference to the overall meaning, but this won't always be true.

-- 
SuStel
http://trimboli.name