There's no evidence yet, at least in this thread (since I'm not a patron), there will be any sex during this event. Including Sophia or otherwise. All we know is that it was complicated, and is the longest event to date (at 380 renders). Anything else, unless a patron can quote me otherwise, is pure (while possibly entirely logical) speculation.
As a shipper of Ellie and Julia (don't worry
farrah, I ship Ellie/Sophia too), on both GW and Filthy, I
really want to see them develop their relationship. But L&P seems to like an infinitesimal burn, so expecting a sex scene this update, while awesome, is probably expecting too much.