> orbits and rogue planets

I think that's an example of coming to a useful realization while working through the process. It should serve to illustrate the importance of not attempting to engineer a particular outcome. If the earth were wandering the galaxy clearly it should still be considered a planet, no? And were we living on a body the size of mars that orbited a gas giant we would still be said to occupy a planet. At least assuming the goal is to classify things of a vaguely earth-like nature.

I think the more difficult question is what exactly qualifies as a moon. Anything orbiting a planet, including a smaller one? That seems perfectly reasonable to me. (Yes yes I know the barycenter matters.)

And yes, I think ganemede should be considered both a planet and a moon. That thing is on the same order of magnitude as mars. What useful purpose is served by excluding it as a planet?