Also, I choose to headcanon that there is a staff of cleaners who comes in at least once a week, and a staff of groundskeepers ditto, because there is absolutely no way that one person could feasibly take care of all that and cook and be Batman's logistics guy. Even if the guest area is usually closed up and the servants quarters are permanently mothballed, that's a lot.

Yes, THIS! Part of historical fiction and fantasy that so few get right is the absolute ubiquity of the servants. I woould also think that for parties they bring in catering staff. There's probably a few bonded companies that they use, and a whole extra level of checking that Alfred does.