So I was creating another throuple playthrough, when I fucked it up at the 11th hour (Lena had sex with Ivy on Ivy's birthday and encouraged Holly to join them in the shower). Interestingly though, Ian still has several thoughts about Lena throughout the beach house, and Lena has several thoughts on Holly to start her vacation with Seymour, while Holly obviously seduces Ian after Lena leaves. Perhaps the throuple flag isn't set for relationships, but it still seems like a strong chance at a threesome between them all might occur later, just perhaps a lot sluttier than the one we got on the beach.