Just beat the campaign. It's left open, basically just the chance to cure it available. You don't see anything else of the Doctor later on.
As far as I can tell, yes. Dr. Hansen somehow finds a cure and uses it before anything gets infested to the point of military intervention. The only thing you have to fight in the "Safe Haven" mission is the Protoss who still are hell bent on wiping out the colonists. On a similar note, I originally had sided with Dr. Hansen to play the "Safe Haven" mission. Later on I went back to the archives and found I could play the other mission "Haven's Fall", and I preceded to WTF as I was launched into a mission with Zerg infestation everywhere. Doesn't seem like Jim Raynor's decision could change reality THAT much...
Don't you know? The big dark evil thing in Zeratul's/Overmind's vision of the future is actually Jim Raynor's dark side. He is actually the most powerful psychic ever and his subconscious has started to develop its own personality and warp reality. That is why Kerrigan has been attracted to him, psychic stuff.
I feel like the two choices were inconsistent with their outcomes- choose to help the Protoss and you see not only an infestation but an actual Zerg base on Haven. However, if you choose to fight the Protoss you don't see even a hint of infestation or the Zerg: just a bunch of cowering innocent colonists with the "evil" Protoss coming to destroy the colony. It would have been nice to at least hear an update from Haven after/if you saved it, whether it was infested or not.
True, but SC2 is all about making things overly obvious... I'm not entirely sure why but it's probably got something to do with films doing the same mistake. The cure I expect to be found in one of the expansions though... there will probably be a mission where you have to protect a certain chained infested being until it's been cured, with waves of Zerg trying to reclaim it.
The campaign seems to leave an open end if you chose to save Haven- I wonder if HotS will be different depending on your choice, if Haven will be completely unmentioned, or if one choice will be made cannon. I still feel like they made the outcomes of the Haven choice incredibly inconsistent in the name of making a mission- perhaps the Haven's Fall mission implies that you waited awhile before checking up on Haven, thus allowing the Infestation to occur? And how did the Zerg set up a base on Haven with it being right by Protoss space? Did a few drones somehow sneak onto the ship going to Haven, or were the Zerg somehow called by the infested Terrans? Theoretically even if the infestation took place all you would see would be a bunch of Infested Terran, since it takes specialized organisms to infest, I think.
