Wikipedia doesn't say anything about the mythological berbalangs being monstrous only in their astral form; on the contrary, it says their slit pupils (apparently their only obvious monstrous feature) are present whether they're projecting or not, and that they always have to eat human flesh; they normally get it from corpses, and project just to feed more easily from living victims. Admittedly, the mention of their wings is a bit confusing, and I'm not clear on whether they have wings all the time or just in their astral form, but aside from possibly the wings there's nothing there to imply they become more monstrous when projecting. Granted, the quoted does refer to them as the "people" of a certain village, but it's not uncommon in mythology to refer to clearly monstrous races as just another people; cf. the Fomorians of Irish mythology, or even the classical centaurs. I certainly don't get from the Wikipedia article that the mythological berbalang is just a "human who's an astrally-projecting cannibal". (Unless you're getting your information from a source other than Wikipedia, in which case of course it's entirely possible that you're right and Wikipedia's wrong; I know Wikipedia isn't completely reliable.)
In any case, though, no, I have no intention of modifying the berbalang to be closer to the mythological original (which I guess makes the above paragraph moot anyway); for my purposes it's the D&D version I'm interested in. If it turned out that the Creature Catalog conversion wasn't OGC and that I had to fall back on the mythological version, I was just going to mention the berbalang by name and maybe a few details common to both versions (like its wings), but not mention anything specific to the D&D version, so I could leave it implied that it was the D&D version that was meant without actually explicitly stating anything that wasn't mythological in origin. Fortunately, it seems that the Creature Catalog version of the berbalang apparently is OGC so I don't have to do that.
In any case, though, no, I have no intention of modifying the berbalang to be closer to the mythological original (which I guess makes the above paragraph moot anyway); for my purposes it's the D&D version I'm interested in. If it turned out that the Creature Catalog conversion wasn't OGC and that I had to fall back on the mythological version, I was just going to mention the berbalang by name and maybe a few details common to both versions (like its wings), but not mention anything specific to the D&D version, so I could leave it implied that it was the D&D version that was meant without actually explicitly stating anything that wasn't mythological in origin. Fortunately, it seems that the Creature Catalog version of the berbalang apparently is OGC so I don't have to do that.