Oh, alright - except for Codenames
No, this is NOT my bloody "fursona"
Card 309 mentions a robot’s building. Is that the Smithy?
Card 234 mentions a ghost’s building. Is that the Haunted house?
We guess so, but why do they have different names?
You guess wrong. To summarise (and answer your second question):
When you place a minion on the board, you gain a bonus.
If anyone else (but not you) plays to that building while the minion is there, you gain the bonus again.