In the demo it doesn't really matter which option you talk to or what activities you do, in general if you want to see a specific scene of one of them you have to remember to choose the Jock during the training section right for the shower scene, for example if you choose 'Coach Hello' you will end up using the shower with Derek, if you chose 'Grey Sweatpants' it would be Zayne, regardless of the other options you ended up being noticed by another Jock.
The second thing you need to pay attention to is on Feb 25, the Jock you meet last will probably be the one you end up trapped in that room after the photo session and the second scene where Jacques messes everything up at the end.
(I will play again to confirm, because as I mention below I ended up facing some problems while playing.)*
The last one is Ace's first time, the Jock you choose to act with you in that mini game will be the one you record with, regardless of the previous choices.
(If I'm not mistaken, I ended up doing the second scene with Leo, but I ended up recording with Zayne, because I chose him in the mini game.)*
I don't know if it was the game or my notebook, but unfortunately I had problems, like for example a bug that appears when you are going to use the drink, it disappears and the game has no option other than to see the gacha toy item, this usually happens if you are going to play again, I was trying ALL possible routes to find out which option fits each Jock, well coming back, I was compatible with Zayne and my choices led me to Bryce, just like in another attempt I was close to Leo and I ended up recording with Zayne.
when I have more time I will try to play again and continue tracing the perfect route for each one, it is difficult since this demo is more than 2 hours long, I am afraid of using the skip and the bug I mentioned appearing again.