How about we combine the works of H. G. Wells and other authors like in Scarlet Traces? Think about it! The Martian Overlords would be fighting against the Green Martians from Edgar Rice Burroughs' Barsoom series and the sorns, hrossa and pfiltriggi from C.S. Lewis' Out of the Silent Planet, where they would be slowly losing the war, thus creating another need for invading Earth: Establishing an outpost on a better planet to outnumber the enemy! Then the Earth-Mars conflict would be moved to the Moon, where Selenites from H. G. Wells' The First Men in the Moon would join the war! And maybe there could be Venusians, too! They would be terrorists! It would be like League of Extraordinary Gentlemen Volume 2, only way better! HYPE! HYPE! HYPE!
Geez, we'd better move this conversation to a new topic.