I was going to make a pic with all your ideas combined but I found a line drawing that already had them, I think it's a design for a late model He-III that never went into production.
Do you need additional crew with that increased armament? Im also not sure if you can fit a side gunner into that stepped nose right infront of the main flight deck. Its surely not going to be a popular position. Otherwise a realy awesome idea! German bomber procurement was a bit of a mess and I can totally see them trying something like this instead of going with the massive overhauls of the Do-17 family (though I expect that airframe to have more potential overall than the -111).
That is rather close to what I had visualized / The only differences was no side positions as that would have inceased the crew size & I had not thought out that cockpit that much beyond thinking that some thing had to change
The design appears to have two side gunners on both sides but I think the forward side guns were to be manned by the co-pilot and the bombardier which is too much work for both crew men IMO.
I believe later model 111s did have the side guns just behind the wing. However those side guns in the nose would be problematic. I can see the prop/engine being accidentally hit by the gunner(s).
It's the tail, it came from a post war tupolov jet bomber that was probably inspired by the B-17 or 29.
The stepped nose with the glazed gun position is also quite B-17ish.
Oh you are in for a treat! "Luft 46" refers to german experimental designs from the very late war, very often pretty outlandish napkin drawing stuff that would not have been realy pratical in reality.
