do you think that muses and lords of aspects other than calliope and caliborn could, potentially, possess some similar story altering effects that they seem to have through their aspects, or is that just a muse/lord of time/space thing since those particular respectively represent pacing and setting? for example, do you think a muse of heart would be able to have an effect on a hypothetical story throughout their aspect in some way?

Every single Aspect reflects a part of the story as well, not just Time and Space, so yeah.