Planet types and atmosphers cannot be editied.
So they will have to be remain the same. I guess they can be explained away by localized habitat phenominon. Make all the races ROCK - Oxygen and if possible set up the mod to use more rock oxygen types than other. Some islands are more hospitable than others, and have better resources while others are less hospitiable, and my be poluted with poor resources.
Making the island images is going to be the hard part. As for ships, planes, and other images, well those will just take a lot of time.
To begin with make one basic set for all with differant flag and emblem colors. The ships will all look pretty much alike but will have a differant color strip on them like in Empire Earth.
How would we use satellites and DRones? Drones could be ICBM's, and Satellites could just be that, Satellites.
Weapon Platforms can be ground based AA weapons and or Surface to Air and Surface to Surface (SAM, SAS) sites.
Fighters will be a focus for the mod of course as the players navy should focus around the carrier as in RL.
The mod does not have to be based on earth, it can be based on any planet.
I think it would be a fun mod to try and make. I don't know about playing, but that too would be nice. In stead of glassing an island a player would have to land troops. Give islands a heavy defense bonus, and set most weapons to not target Islands (planets).
The propulsion system will need to be figured out though.
Long range fighters can be small ships (set up to be fighters if possible.)
Mines are mines are mines.