I agree that image does appear reasonably free of sensor noise, or at least the JPEG artifacts are hiding anything that might have still been present.
What I mostly had in mind was the kind of egregious color noise that @PM490 was describing with the single-pixel rainbow speckles. In dark areas it can get pretty distracting. Although, I suppose that is exactly what the additional, longer HDR exposures are intended to fix.
Once I get to the exposure fusion step, I was hoping to test both together in the way you described. My particular camera is streaming full-res, raw images at ~40 fps, so averaging several extra images together can be done in under 100ms. Doing that at each exposure value doesn’t seem like that bad of a time hit. (Especially when they’re “free” exposures that don’t need to wait for motor settling time or other changes in the system.)
That said, if there isn’t any perceptible difference, that is time that could be better spent making the rest of the process faster. I’ll try to quantify it when the time comes and–as always–report my results here. Thanks again for your input. 