Let It Be Night
Rei has always believed that Venus' memories are not truly Minako's. Whoever Venus was, eons ago, she was not Aino Minako; the soldier's soul was tied to the Guardian Power that, thanks to Usagi, was no longer theirs. That power, and the memories that came with it, are an inheritance from long-dead warriors, rather than something intrinsic to these four girls. Women. But not soldiers. Not anymore.
Makoto and Ami, like Rei, never had anything more concrete than feelings, and as time went on, even those have faded. The former soldiers of Mercury, Mars, and Jupiter seem perfectly content not knowing more than what they have learned as Guardians. Usagi, on the other hand...
For someone as outwardly air-headed and flighty as Usagi, the part of her that had been Serenity still frightens all of them, and no one can shake the feeling that someone as powerful as the former Princess of the Moon can never truly disappear. If Usagi remembers anything - quite unlikely, because she never remembered her brutal actions as Princess Sailor Moon, and only remembered the outcomes - she doesn't say. Not would someone as kind-hearted and sensitive as Usagi want to remember the events that drove the Princess over the edge.
But this does not explain why Minako's memories, those damned memories, linger. She never speaks of them, as the future now preoccupies them all, but Rei has a feeling that they must still be there. Perhaps because Minako dwelt on them, lived only for them, for so long. The Guardian Soldiers, Venus especially, were all about sacrifice, and Serenity accepted it, even exploited it. But Usagi is not Serenity - she said as much when they were younger and Serenity was still awake - refused to be her, hated being her, although she could not hate Serenity herself.
All of this, however, Rei keeps to herself. She has no patience for the arguments that will definitely erupt if she brings it up, because Minako has everyone else convinced that they are still the Guardians. Present tense when it should be past.
It is not a matter of whether Rei hates fighting or not; she will always fight for Usagi, for all of them, because they are her friends. It is not a matter of whether Rei believes in reincarnation or not; for the record, she does.
It is a matter of the deepest kind, where she cannot understand - and she never will - that Minako, the idol whose songs were rumored (with some validation) to encourage others to live, would want to die because of something so old and so far beyond her mortal reach.
If Venus truly were Minako, then Minako would have been justified.
Rei won't accept that.