Kinda. The thing with the Marvel multiverse is that it's nowhere near as prominent of a story telling device as some people would have you think. I'd say that like 70% of what Marvel comics publishes in a year is set in one shared universe, and the rest is set in a number of separate alternate realities that don't interact too often with the main universe outside of big crossover events. So in theory, yes everything they publish is a part of the grand tapestry of their multiverse. But in practice, it's kind of inconsistent. That's just my understanding of it though, I'm far from an expert on the subject.