I'll only tackle question number two; what happened when Luke went down at Murveaux?
Several contemporary historians have tried to discount the story of Luke's alleged shootout with German soldiers in a farmer's field outside of Murveaux, but none have done so with any reliable evidence. Case in point, the
Above the Lines/Over the Front/etc. series, which summarily dismisses the shootout without so much as a consideration. They offer no explanation whatsoever, other than saying that Luke's career needs no such embellishment. Admittedly, the story sounds far fetched and is certainly suspicious, but in order to discount a written, signed statement by a number of actual eyewitnesses, including the town mayor (whom one would expect to have some marginal amount of credibility among his people), you must present some sort of evidence to back your argument. I have seen none. Therefore, to my mind, the story stands as it was witnessed and reported by the people on the scene, regardless of how outrageous it sounds. Until something else comes to light, that's the only rational way for an historian to look at it.
As many of you know, I've been to Murveaux and will return in about 13 days (YAHOOOOOO!!!). I've seen the exact spot of Luke's demise, and the shootout story is plausible IF you discount the imaginative theory of his ending up in the graveyard, which is at least 500-700 yards from the landing site and clearly had nothing to do with the alleged shootout. Otherwise, Luke's supposed strafing run on the troops in Murveaux lines up perfectly with his landing site. I.e., the main road in Murveaux on which troops were reported to be standing makes a perfectly aligned target from the direction of Luke's approach, and a wounded man who wanted an immediate landing would have landed in the open field, directly beyond the main road which is indeed alongside a VERY small stream. Luke's plane would have touched down less than 10 or 15 seconds after his strafing run. He could have been out of the cockpit and at the stream less than 30 seconds later. Give him 30 seconds on the scene... enough to realize the gravity of his wound, make his decision and get his weapon, and you have just enough time for German soldiers to arrive on the scene. I do sincerely doubt that Luke was able to take any of them out, since they had a clear shot at him with their rifles which had a much greater range; therefore it's logical to assume that they opened fire on Luke as soon as they realized his intent to defend himself. So logistically and geographically speaking, the shootout story can't be disproved, and historically, we are still stuck with the signed statement of eyewitnesses whether we want to believe it or not. The only possible negative evidence may come from the USAF officer who visited this area and spoke with witnesses many years ago, and I have no knowledge of what his research found.
Sorry for such a long entry, but I felt I had something to offer on this particular question.