Cooperative project revival

[Ghostman]

1- what projection should be used?

If all the individual overland maps are done in equirectangular projection then the main map (overlaid with the user-created parts) can be reprojected to any other projection afterwards.

2- what kind of landmass do we want ? and where on the map?

3- what about the univers surrounding it... how many satellite orbit around the planet ?

4- 1 or more stars in the system?

5- planet tilt

6- will it be an earth-like climate? colder, hotter...

Something fairly Earth-like might be the safest option for a cooperative project. That way there'll be an interesting variety of different terrain and local climate conditions for people to choose. Whereas something like eg. a "waterworld" type planet or one that's all deserts would be problematic. There may be more leeway when it comes to things like suns/moons/other planets, depending on how realistic (if at all) you want to get with the astrophysics and all.