How are they going to prove which one, there's presumably no physical evidence?
There SHOULD be evidence though, there should be a log of who his security officer(s) were and where they went with him. If this is missing it is suspicious.
If he did take his daughter to a party then surely the girl whose party it was, or her parents, should be able to tell what time the the party was.
Ghislaine maxwell will be looking to do a deal, she is facing decades in prison, who knows what she will say at trial and what else may come out.