...I appreciated Martin's use of the Gnalish, whom (I presume) Michael Jan Friedman invented in Reunion.
He did, but with an asterisk. Sometime after the fact, a fan (maybe even Therin
?) suggested to Friedman that the reptilian character Sord from TAS: "The Jihad" might be a Gnalish, and I think that idea has come to be pretty much accepted in the literature. So in a sense, a Gnalish character existed before Reunion
, even though the species was invented in that book.
The caste system was interesting, and the source, perhaps, of the different appearances of TOS's and ENT's Gorn creatures.
That was the clear implication. The description of the warrior caste matched that from "Arena," and the description of the technical caste matched that seen in "In a Mirror, Darkly" -- which is consistent with the Gorn in IaMD being the slavemaster of a group of engineers.