At the risk of sounding didactic myself….have you ever read the classic child-rearing book, “Children: The Challenge”? In essence, the book advises applying the “natural and logical consequences” to a child’s bad behavior rather than bickering, punishing and fighting endlessly over the same issue.
As an example, my friend’s daughter refused to get ready for school. Every morning brought the same battle over her tardiness, until one morning –nothing was said, and when it came time to go to school she was simply carried to the car in her pajamas and delivered to school on time (pre-arranged with the teacher, of course). That ended the problem without another word.
I firmly believe this technique applies equally to adults, though perhaps with more subtlety. The point is not to humiliate into submission, but to remove oneself from the angst and resentment that causes ill will….and show who’s in charge at the same time!
As others have suggested, simply putting breakfast out at the requested time, accompanied by a polite warning knock on their door, then happily going about your business would have satisfied your obligation and prevented all of the hand-wringing.
However, the bathroom situation would have required some creativity. Remove all reading materials? Turn off the heat? Knock on the door every 15 minutes and ask “how much longer”?
Again, this is not about retribution or teaching a lesson as much as it is about saving your sanity while hosting dreadful guests.