Unfortunately I can't offer any thoughts on the possible new muses, since I've yet to get into those fandoms. :c

Her being cautious while trying to remain optimistic... augh, that's a familiar one. Luke's trying to do just that. There's a good reason for him not being eager to return home, after all. We need these two to bond over world-hop feels, as you said. :|; He needs more people to befriend over this, as I'm sure she does, as well...