Indeed (Toaq Dzu has both as distinct words). I take {ro'oi} as the dual
of {su'oi} (naku su'oi naku). The other one would be "the highest
number". My impression so far has been that "any" is much more common
than "all". "All" is mostly necessary when counting cardinalities (e.g.
"All shipmates together were seven in number"), where "any" would fail.
I just think that plural quantifiers would make more sense in a language with plural reference. Right now Lojban has a strange mix of singular and plural predication. We can talk about the students who are surrounding a building, but can't claim that some students are surrounding the building without bringing in proxy sets or masses (or experimental cmavo).