If we consider the parallel story canon, even in the manga they seem to be able to have their own private lives. I ship Rei and Minako in PGSM, but the manga thing never really seemed to me as anything but fans sering things not quite there. The same way I never seen Hotaru and Chibi Usa's relationship as romantic in any way, but some do. Makoto and Asanuma were so cute, so in my head this is an actual relationship that simply happens behind the scenes. Minako might end up living the celebrity style of wife, 5-6 marriages and divorces. Ami said in act 5 that she wants a traditional wedding kimono, so in my head she is a more traditional kind of girl. She is also shy and mature for her age, so she might like many Japanese women end up with a guy slightly older than her, a doctor most likely. As for Rei, ironically, I think she will end up with a politician or someone with blue blood. As for Pluto, as unethical as it sounds, wasn't she quite close with that unseen professor she worked all the time and had dinner with in the science lab?