There are realtor notes that go in-between realtors. Nothing super secret. Things that come with the house vs what doesn't come with the house are most usually in the realtor notes. The buyer agent can discuss them with their perspective buyers.
So I'm assuming that one of you all would want to put in an offer on this house, and it's my responsibility to let you all know the sound booth doesn't come with the house.
As for the lady who wants to live in the garage for the next 10 years, you would know from your agent that the lady would want to live in the garage for 10 years, you wouldn't put in an offer, the current owners would tell the lady to get out, and you can buy the house without the lady in the garage