I wonder why they were able to use M'Ress but not Arex.
Power Records used M'Ress's name and race, but she was drawn as a bluish humanoid (seemingly based upon Marta the green Orion from TOS). Perhaps that audio script had already been recorded?
Passage to Moauv
by Therin of Andor
, on Flickr
It appears that the problem was with the physical look
of the supporting characters of TAS. Perhaps there was too much red tape working out if Filmation would be owed $$$? We also have a blonde, caucasian Uhura and a Sulu with dark skin and an afro hairstyle.