Glad that I was able to help out! I'm happy those links have saved you many hours of tedious screencaps and frustration.
Many of the maps I found online where from 3D0, but there are indeed many fan-made compilations that have been attempted to be put together. I just looked at the map, and it is a Wake Of Gods Map (a very excellent fan-made expansion, still deciding on if to incorporate it into this mod). Very detailed also, I haven't started making the map yet, but this will come in handy and I will use it.
Yep, it's got In the Wake of Gods written on it, but it hasn't really got anything to do with that expansion. WoG doesn't really follow the "proper" Heroes storyline, although that map is based on commentaries and directions from the NWC world developers. It was actually made to celebrate the tenth anniversary of H3's release (that long already?).
Though there are many official maps of each continent, there is unfortunately not a single official full world map for the planet of Enroth. The calendar one I believe is the closest you can get.
As far as the Vori goes, they were partially in one scenario of HoMM3, but there seems to not be very much information about them (although I would have to look a little more than I already did a while back). I was thinking about adding them into the mod, but without alot of graphics and creature lines, city names, etc... too much would be missing.
Vori is a bit of a mystery, true - they are in Heroes Chronicles, but are only represented by the Rampart (AvLee), not an all-original faction as they should have been. There were many details given in MM8, though, probably enough to get a faction out of them with a little imagination and speculation. We know from MM8 that Frost Giants dwell there, and you could fill two more tiers with Snow Elves and Snow Elves with a mount (like the Rampart), so you just need to think up four creatures, like Wisps or Mammoths, to fill the blanks.
City names aren't too much trouble; we know there's one Vori town named Seelie, and the rest can just be invented at will. The main problem, I think, would be getting a decent graphic for the town itself, but you guys are obviously talented enough to work through that.
I don't believe Enroth or Jadame was used in Heroes 3. I may make a map that includes them though, as well as a map of only Antagarich. I have not started either yet, but one question we were looking at earlier was trying to find a map where specific cities were, of course I don't think one exists. So if I create a map, it's likely the cities may just be randomly placed, or randomly named, unless I can locate something that may help.
That is a bit of a problem when inventing fanmaps for Antagarich and Enroth because many towns are so abundant and randomly named that some just have to be ignored. Jadame is much easier because it hasn't been in a Heroes game and all of its town and city positions and names are 100% defined.
I can give you a few links to some of NWC's "bonus lore" which indicates the position of several cities. Tatalia, Eeofol and Erathia have many, many named cities with definite positions on the map, while the other nations get a bit more vague. This is probably just semantics though and I realise that the main thing for now is getting the modding done

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On a side note, if you'd like any details or texts for the Civopedia, I'll be happy to oblige! There are a lot of little pieces of Heroes III lore you could fit into descriptions and things there. Thanks a lot for the warm welcome and best of luck with the modding! Looking forward to playing it!