To me, the term "QM" refers to something that includes the correspondence rules that tell us how to interpret the mathematics as predictions about results of experiments. (QM is a theory of physics, not a piece of mathematics). So the kind of interpretation you're talking about here is already included in "QM".Not really. In order to apply QM you need a way to map the mathematical elements of its formalism to stuff out there. That's the job of an interpretation.
So to me, an "interpretation of QM" is something else; it's an answer to the question of what's actually happening to an isolated system. But it can't be any guess. It has to be an answer that follows from QM itself*, once we have made a few statements about how to think about some of its mathematics.
Martinbn made the comment that when I tried to partially define the MWI, I seemed to be just assigning familiar but undefined terms with mathematical concepts. It seemed that way, because it was that way. I don't think there's any other way to define an interpretation of QM.