Ahhhhh! A Sephiroth!!! I'm definitely game! Whichever you prefer is more than fine.

If he's a past lover, then expect Ashura to flirt regardless. He's not the type to have bitter feelings about things.

As a lover, Ashura would probably spoil him with gifts, because it's fun! He would probably also rely on Sephiroth to be the "more responsible one", should Sephiroth so accept this quest, lol. As well as maybe try to coax Sephiroth to participate in his public performances? Plays, dances, and the like.