Outside the field of anthropology terms like this lack firm definitions. They're social definitions designed to allow people to quickly categorize individuals according to certain stereotypes. The entire idea of a stereotype is to ignore granular differences - which all people have - and use broad strokes to generally describe a person. Since both of these words essentially look at the same stereotype then they're both interchangeable.
I believe the terms 'yuppy' and 'bohemian' are interchangeable. To me both terms bring the same image to mind, but it's more of a lifestyle term or a term used to describe a way of dress. I believe you could also group the hippie crowd in with these terms and you get the political ideals as well. I would say of the three, it's possible that yuppies, might come of as somewhat offensive.
Yes, I think that the terms yuppies and bohemians are interchangeable, because they are essentially the same thing. A yuppie or a bohemian does not plan for the future, put down roots, or have traditional family values. To say that they are different is to have a distinction without a true difference in what they actually believe.
A yuppie is someone I think of as an 80s relic. A Baby Boomer, part of a generation of such unmitigated greed and devoid of ethics, directly responsible for the fiscal crises of the 21st century. When I think of Bohemians, I think of people who are artistically inclined, unconventional, but contributing to society. In other words, the terms could not be further apart.
No, a yuppie is just a person that is from the city and that does not know how to live in the country and do things that an outdoors person would know how to do. This is a lot different from a bohemian, and they do not have the same.