You're kind of proving my point here, because you're right, Galaxy does evoke space, which is shown through its premise, setting and level design. However, the Spin, which can be incredibly useful, is not referenced in any way on the title of either game.
Even Sunshine kind of has that, as "sunshine" evokes either summertime or a tropical place, and what is Isle Delfino? A tropical resort island. While F.L.U.D.D. does fit the overall theme of it due to being basically a versatile water cannon, it is not what the title focuses on there either. It could very well have had that name without F.L.U.D.D. because it doesn't take away the tropical setting, like how removing the Spin in Galaxy wouldn't take away the intergalactic setting.
As for Odyssey, well, I don't think it's a coincidence that the game's name is similar to that of a
certain Greek epic. Both are about a man traveling the world to reach their beloved and both also have someone trying to take that beloved's hand in marriage in their plot as well. Take away Cappy and the overall premise would still justify the name of "Odyssey" because its story still shares similarites with the original Odyssey.