So I did a bit of research into this, and I'm pretty sure these are maps for RealPolitik.
Calhamer's earliest drafts of Diplomacy were called RealPolitik, and there is a surviving rulebook to this - http://www.diplomacy-archive.com/resources/rulebooks/1958draft1.pdf
Reading through this answers questions 2 and 3, but I'll get back to them.
The coloured board is almost certainly the most developed version there, and Constantinople is definitely one province on that. The nametag has arrows pointing to both landmasses, and since the sea in the middle is unnamed, I'm fairly certain it's supposed to work like Constantinople in the Classic version.
Side note - the Kiel canal is clearly also there, see the sketch.
The unnamed province just beneath Con is Smyrna - you can see that on the sketch. It's not an SC in this version.
The starting positions of units is something I haven't found the answer to but I think I can guess after reading the old rulebook. You need to understand how builds work in RealPolitik first, though.
You see the anchors and stars on the map? Those are naval bases and capitals respectively. In RealPolitik, each country is only allowed to build in these centers - all fleets must be built in its naval base (or one of the two naval bases in Russia's case) and all armies must be built in its capital. If the capital is taken it can be resignated to any other HSC, but if your naval base is taken, you can't build fleets until you take it back.
You *can* build more than one army/fleet in the same year, though - the capital and naval base can contain as many of your units as you want, although I believe they cannot support anything while there is more than one of them there.
It's not stated in the rulebook, but I believe that the game was supposed to start on a build phase, and so you could decide how many of your units to build as fleets in your naval base(s) and how many to build as armies in your capital. Supply centers like Liverpool or Cologne are supply centers which begin the game controlled by their respective Great Power and so help them build their starting units, but you cannot build units there and they do not start with units.
Obviously this doesn't work on vDip, so you're going to have to find a way around it... But what it does mean is that England isn't army heavy as you would think from the map, it's actually just a quirk of the old rulebook.
Regarding neutral centers, the rulebook says that 'Each of the Lesser Countries is a supply center.' My guess is that this means any country which was not under the control of another country, which matches up pretty well with the shaded centers on the sketch (the African countries on the board were under the rule of European powers at the time, Transylvania was under Rumania, and I believe Montenegro was under Serbia).