Rose, Peter, Hayley, Scott, Marina, Zoe and Leanne are my only people NOT on Mars right now, but Alicia will be there soon, so that's not a dealbreaker tbh.
Tiny, correct me if I am wrong, but Oliver stayed on Mars after his failed attempt to find Barry with Margo, right? Lol so I think he is there either way.
Barry is probably the only one of mine who isn't an option because of the aforementioned being very kidnapped.