Surviving Mars and Stellaris can't happen in the same universe.
In Surviving Mars, Earth is as politically fragmented as it is right now (although probably more peaceful, this is an optimistic vision of the future), with each major nation, group of nations or corporation (or even a cult) sponsoring its own colonization initiative. There is no mention of FTL travel but you can terraform Mars once it has been colonized. It remains fairly plausible.
In Stellaris, the entire Solar System starts as one political entity. You have FTL capability but you can't colonize Mars until you've completely terraformed it, and you won't have the technology for such an undertaking before decades. It's clearly more fantasy oriented, with aliens looking...