also, how would you translate the {wa'maH yIHmey lI'be'} ? "ten not
useful tribbles" or {ten useless tribbles} ?

I'm inclined to translate it as "ten not useful tribbles", leaving the
{wa'maH yIHmey lI'Ha'} to mean the {ten useless tribbles}.

I don't see any difference in those translations, aside from one being a more clumsy phrase than the other. CK translates it ten useless tribbles. Useless means not useful; it doesn't mean the tribbles are causing harm.

-- 
SuStel
http://trimboli.name