So, quick check here: you know by Palkia representing "Space" they don't specifically mean outer space but more Space as a concept? Like the spaces things occupy. It's why it's the counterpart to the "Time" pokemon, since it makes up 'spacetime continuum', why if it gets to show things off in other media its usually warping you to different places or changing the orientation of things, and why in LA, Irida focuses on the expanse of the worldthe thing is, while i get these points, their typings particularly would fit better reversed (water as the flow of time, steel as space and stars - meteor mash is a steel move!), and even their designs superficially feel switched to me (dialga looks... spaceship-y?, palkia's shoulder things look like clocks) even if there's obviously more thought in what you two said than in my perception.
(but even with a space interpretation I think Palkia kinda sorta resembles spaceships a little more; mostly the lighter coloring and the sleeker design. also kind of vaguely reminds me a diving suit, I think its the pauldrons)