Another simplification on the body finding mechanism:
Any ship entering a previously unknown system would start looking around for planets, they would scan/photograph in a sphere all around them and save the data. Asuming either bored crewmen with nothing better to do while moving somewhere, or ftl comms and people without anything better to do back home, that data could be anylized without the ship being in the system, removing the need for that check. So upon generating a system, each body type would be given a date for thwn they would be revealed.
Another idea: Planets having a thermal emision based on albedo, distance to star, and star luminosity. That way bodies can be picked up by thermal sensors. And of course any body should be picked up by active sensors.