Kzints are canonical. They appear in Star Trek Animated Séries, " The Slave Weapon "; Your planet appears in a stellar map of Next Generations; It would be theme of a whole episode of Enterprise, if this was not canceled.
Then, Reason that race is not introduced in Star Trek OnLine? Would be the version " Caitian " of the Império Klingon. " Problems of Copright with Larry Niven "? Well, then make possible tails, bat ears and snouts in the elaboration of Aliens that would be already wonderful!
It is just a suggestion of a fan of your work.