I'm at the stage in my steel framed outdoor kitchen build that I'm ready for cement board. I'm doing Durock with the rough side facing out. I plan to put an Oklahoma Chopped natural thin stone veneer on it. I've done quite a bit of research and have seen answers all over the board on this. Do I need to do anything for moisture management? I've seen people say applying the stone directly to the cement board with thinset is perfectly fine. Some say a moisture barrier is needed. Some say a metal lath and scratch coat is needed. Some say metal lath is not needed but a scratch coat is. Some say a weep screed is needed. I'm assuming what I've seen in terms of answers is relative to location and rain amount. This is in North Dallas and it will sitting on Trex board on top of a stain and stamped concrete patio.

As you have used steel framing, I would be inclined to provide a moisture barrier to avoid rust. I'm assuming that by steel framing you mean metal studs and track.

18 gauge galvanized tracks and studs with welded end frames. FYI the entire outdoor kitchen is under cover but on the edge so it will get hit by wind blown rain.

Moisture barrier will stop rain from coming through the veneer, but it won't do much in a high humidity environment assuming the framing is open on the inside and you have cabinet / access doors.

Being in Dallas, this might not matter.

I'm just astounded that there isn't a definite answer to this question? Is it just a preference thing or what?

Honestly, most situations are unique. It depends on the site, environment, products used, and personal preference.

It's kind of like asking a doctor something specific and expecting a definite answer (albeit only financial risk instead of life).