Really, it's ridiculous to insist they must be Caitians just because Damon Lindelof said they were in an interview. Indeed, he didn't even volunteer the information;
the interviewer asked if they were Caitians, Lindelof didn't seem entirely clear on what he was asking about, and then just agreed with the interviewer. That leads me to suspect that Lindelof had no idea what a Caitian even was and just agreed with the interviewer to get past it to the next question. There's nothing remotely felinoid about
the makeup designer's prototype designs, so I doubt they were intended to be Caitian at all.