>>50985942It would've been possible if her anime debut wasn't tied with the return of arguably one of the most debatable character introduced. Or maybe don't make her tie with said character.
If we had another episode with Lisia but without Serena, it might be possible. But the confirmation of the idol duo essentially tied her up with Serena as a packed bundle, either those two or nothing at all.
TL;DR: Lisia's identity is sewed onto Serena.