I agree it's realistic that an organisation like PHALANX would have access to all blueprints of military areas like bunkers, and of some shopping centres. And truely it would be possible to look at the place via sattelites or from the ship itself to get a birds-eye view.
Maybe it could differ from mission to mission depending on how much information you have. In a bunker you start with the full map visible, but there would be "fog of war", which generally would give you a better idea of how your line of sight is (as it is now, you never know where/how far your soldiers can see). In case of base attacks there could be security cameras around giving you some of the map fully visible at all times, and in case of no building plans, like the farm, everything inside should be black until you explore.
Maybe integrating a mission planner would be a nice idea?
It could tell you if there are civilians to take care of, and how many aliens that have been reported, if known. (nice if there could be a mapoverview, where you could find the best place (I mean: pick the best spot) to deploy your soldiers).