Lily and Suzu being okay with the harem plan makes sense, as well as Lily's demand of being the legal wife.
Even if she was disowned, due to her social standing she'd have to be the legal wife if Girold doesn't want her to be seen as disgraced.
The only problem would be Alicia agreeing to it, considering she confessed first and Girold already confessed to her as well.
But if I could yell at Girold...