Unfortunately it was a useless hope.
I walked the path of the "good" Bully, I didn't take advantage of Celine and I never gave in to Lia's provocations (if something similar happened to me in real life, I wouldn't be able to say no). Unfortunately Eva doesn't tell her in any way what happened to her on the pirate ship: only a couple of times, as soon as she arrived on the island, MC asks her what happened and in a very evasive way she only replies "I'm fine", "everything's fine". ", but since they had to hurry to leave the island, the story is never told... not even in the future. As mentioned, it's clear that something happened on the ship, as she eventually became more sexually open.
Adding content to the full game now would be useless, to find it you would have to redo the game from the beginning, however an extra minigame that would only show Eva's 5 days (July 18-22) in the company of pirates wouldn't be a bad idea. A separate episode called "Jolly Roger" or "The Pirate Ship"