I actually think {tu'a} deserves its own selma'o. Not only is it different from the other LAhE, there is also a proposal to allow {tu'a} to work on tag-terms:
tu'a bai ko'a -> lo su'u bai ko'a zo'u co'e
There are no obviously useful corresponding forms for the other LAhE, so I would personally be tempted to move {tu'a} to TUhA rather than creating a bunch of meaningless but "grammatical" forms for non-{tu'a} LAhE.
In a similar vein, I am for splitting up the PA selma'o in order to outlaw the many nonsensical grammatical PA-strings and to give the meaningful PA-strings a proper parse tree (which they currently do not have. The meaning of complex quantifiers corresponds only rarely to the structure the parser suggests).