I'm not saying Ellie will tell Sophia that, I'm saying when Ellie is talking to Logan, he will mention and talk to Ellie about her new boyfriend, and then during that Sophia will realize Logan is talking about Dylan.
Ellie and Sophia may run into Logan at the spa and then what happens next depends on whether Ellie has dumped Logan.
So, therefore, we may see them in that teaser no matter what choice we make, but if Ellie has dumped Logan, it will be Sophia and Ellie going into the spa together. If Ellie hasn't dumped Logan, then it's Ellie and Sophia joined by Logan and his friend.
If Logan and his friend join them both, then the choice regarding Sophia being topless in front of strangers in the spa might come into play. Something that then might play into the Ellie Bitch setting we all know is in the background and maybe this is the trigger for that.