My idea for that scene, however controversial, would’ve involved ghost Anakin taking a holoprojector from the DSII wreckage and showing Ben a small recording of Padmé. Anakin would talk about his regrets and how he could never see her again, warning Ben profusely about his path. It would parallel Rey and Luke’s discussion, furthering the dyad theme.

If ghost Anakin is more involved in showing Ben the light (or has his own arc through the ST of helping the heroes), perhaps a reunion with ghost Padmé would be a good (albeit cliché) touch.