It got so complicated that the (never made) TOS-era New Voyages fan film adaptation of the (also unmade) Enterprise season 5 Kzinti episode "Kilkenny Cats" chose to swap the Kzinti for the Kythari (sp?), a feloid race from an officially published Trek short story. 90's TNG novel The Captain's Honor features the M'dok, who were originally meant to be Kzinti. Picard showrunner Michael Chabon sought Larry Niven's permission for the Kzinti namedrop there. But a namedrop is one thing, featuring them is another.