by Shmello50
In skimming the rules, I have to admit to the OP that these interpretations (which I believe are definitely correct) are not very clearly indicated. Two of them you kind of have to understand by inference.The clearest one is the no re-use of a building. It's in the margins on page 5, opposite the building action explanation. It says that:
A player may not re-use a building that already contains his Person disc.
So from that you know that you can't re-use the building. You can also infer that you're supposed to leave your disc there because otherwise how could it still contain his disc? You can also infer it from the buying and selling buildings rule (page 6) which tells you to return any occupying person discs after these actions. You wouldn't have to return them unless they were supposed to stay there until the next use.
The final action after the final feeding rule is contained within the Final Stage rule on page 9. It says the last round card is resolved and then the final stage begins. If you look at End of a Round on page 7, it describes how to resolve a round card, which includes the feeding phase.
It's all there, but perhaps not as explicitly as it could be.