Not sure why you're thinking about these hypotheses as supersets and subsets of one another. If I wanted to get formal with it, I'd describe the hypotheses as programs. The design hypothesis would be an agent program that outputs our local universe by building our universe the hard way. The chance hypothesis would be a set of physical constants with rules determining the time evolution of reality that outputs our universe, and not an entire multiverse of which our universe is a small part. The ensemble hypothesis would be an even simpler and more fundamental set of rules than in the previous program, maybe with some constants as well, and it would output a multiverse, some parts of which are hospitable and even identical to the previous program's output. It confuses me to think about these hypotheses as subsets of one another, because it makes me think of substrings. These programs would not be substrings of one another. Their output would be though, because they all output us observing our universe. We're supposed to be talking about hypotheses, not output.