Indeed ...
But even that can be aranged!
Since patch 3 or 4 ... not really sure now ... Larian changed that vendors, when killed, no longer drop all their inventory, but only small portion (the rest probably vanish in the oblivion or something ... not really a fan, but i digress)
Therefore we know it is possible to make inventory =/= loot ...
So all we would need is Lae'zel vielding her armor with "Lae'zel only" atribute ... but if killed, simply drop regular "Githyanki Half Plate"