Hangarshuffle (your #3).
Could be pressure marks from a tight fitting mask (and there might have been some grease which had got onto it, as suggested). Don't think blood - at least not his, but he might have been attending to a wounded crewman).
When there's blood, there's usually a lot of it.
But what wonderful photos ! Glad they put in Clark Gable - he was a bit old (early 40s) for aircrew - but what about James Stewart ? - 25+ misions as a 4-engine pilot and finished as a Lt/Col., I believe.
Danny.