Hello Gordon,
I share your disappointment with the Eduard 1/48 French 1916 personnel and it seems odd that, as you correctly observe, the poses do not match those shown in the box art and that the groundcrew clothing also differs. The same general point is true of the RFC personnel set; apparently the side box small print mentions this but surely one would assume the box art to reflect with some precision the actual contents? From my perspective the greater disappointment is that the stances are so limiting and uninspiring, aside from the mechanic just sitting on the grass.
With a clear, if "off the wall" idea in mind for a diorama, I have shopped around in vain for more enterprising groundcrew. It seems to me that the Eduard RFC personnel set is equally limiting, not least in conversion potential, and driven by the same formula: six figures of whom three are officers/aircrew and three are mechanic groundcrew in uninspiring stances.
My best hope seems to rest with a flurry of releases to coincide with the centenary commemorations over the years ahead. Do let us know if you unearth something new or find it possible to convert what you have.
Best wishes
Nigel