Another then needed change would be to add the "Wadi Tawil" as a "drainage", or playing it will result in massive floods caused by having no route for sewage water to go.

Suggestion: replace the standard highway with the mass transit dual-direction - single lane highway w/o sound barrier and let it go from south to north, with a small intersection (single lane/connector roundabout) to connect another such highway piece from the starting tile to the highway east of it. also you can make the "lake" a bit like a "well", by mapping the area around it normally and then adding a deep pit with the least possible amount of water in it. that way, it should pass the map editors sanity check.
I've also added flight paths for planes and two "dead end" railroads - each coming from one end of the map (north/south) and ending in the outhermost possible tile in order to enable better late-game freight transport as well as building an airport that actually works.

I've implemented these changes in my version I've got locally on my PC.

Anyway, cool to see this here. Thumbs up for making it.

PS: Sadly, the mapeditor also forces a highway into the map, which (like the lake) doesn't exist at all...
The only routes to it ends at it's southeasternmost corner at Bir Hesmet Omar, and is an old, unpaved track that can onlye be driven on with a solid 4x4.
An updated version may reduce the lake's size to as small as possible to represent more the well that is actually in the center.

AFAK, I have no idea how to replace the highway with the classic gravel-esque rural road. I guess this would only work with extensive cheating and even then it would seriously hamper Gameplay after a few minutes...

Actually, none of them wants it, because of the following situation:

Hala'ib would belong to Sudan if Egypt claims Bir Tawil [1902 Borderlines]
or
if Sudan Claims Bir Tawil, Hala'ib would belong to Egypt [1899 Borderlines]

It's basically the question if the 1899 or 1902 borderlines apply - Since both want the Hala'ib Triangle, neither can claim Bir Tawil without saying that they don't want to have the Triangle at the same time.

Effectively, Egypt has occupied Hala'ib, but since Sudan doesn't want withdraw their claims, they won't claim it.

Check out Wikipedia for more info: https://en.wikipedia.org/wiki/Bir_Tawil

Egypt and Sudan disputing over the land?

Thanks.