I can't tell with this one either, might be a bug, sometimes she remains available, sometimes she closes despite my interactions with her being pretty much the same...I have the same problem. Spent the night with her ( when you first meet her drunk at the bar), didn't blackmail her, always get her ( jealous) scene when she warns you about dating principal's daughter. I did a few fast CTRL skip-re runs..but MC always says "It's not my business, after he overhears her on phone".
Elena is so closely connected to Layla that I think what we are going to get is couple of bisexual girls still "figuring it out".There is no single route with Elena yet. You can only see Elena's reactions when you are on the Layla Love Route. The best way to see your reaction to MC after the house visit with Elena and MC says goodbye and Elena says "I know what you mean ... layla. All other interactions with Elena: Pool, Truth and Dare 3 Way kiss indicate a possibly coming one possible Elena route there.
The normally ultra jealous Layla, is kinda open to mixing it up a bit when it comes to Elena.
And Elena kisses Layla before kissing the MC on the train.