Cajun in RTP?
Oh, you're breaking my heart here. Sad to report that the so-fine Taste Of New Orleans is no more, and despite reports of a comeback have not been seen again. Can't even tell you how much I get to missing those Oyster Po'Boys.
There are places that label themselves Cajun/Creole/LA in style, but in my experience are coming up well short of the mark. I'd call what these places are doing LA influenced bar food, and not even all that great by those standards. Nothing horrible, just a pale shadow of what I'm really looking for.
Cajun Charlie's, Morrisville
Big Easy, Raleigh
Best of luck and please let us know what you find.
Yancey's, from my experience, isn't really Cajun/Creole. They're more Southern, with some LA-influences thrown in. And don't bother with Zydeco, either. Terrible, terrible service (I once spent 20 minutes with an empty glass, and 45 minutes for food, before FINALLY tracking down the manager to get service. And when the food arrived, frankly, it was pretty bad).
Cajun/Creole food is one thing that's really lacking in the Triangle. Heck, I've even been finding myself jonezing for Buzzard Billy's Etouffee, and they're a chain! And, simply put, they're better than anything I've found in the Triangle other than Taste of NO that calls themselves cajun.