I'll see if I can break it down by experience/eagerness in another post, remembering that I've spent most of my attention in the Alternate Start cabin with Lisa, Madison, Hannah, and Taylor and need to review the threads leading up to everyone going to The Other Cabin.
I've only seen your edit now, Zingiber. That was an issue I was thinking about how to approach in a way that doesn't limit what you or Yarkoz or Patzo can or can't do. I suppose we should use the character's versions featured in the threads leading to it, and they have a few differences if we compare them with their counterparts at other threads. I'll take a shot here on breaking them down by experience/eagerness like you've said. As always, everyone's welcome to give their opinion.
Zack: Currently split between Victoria (his crush of two years) and Heather (someone he found a great connection with during the trip), had a few sexual experiences with both (performed oral sex on Heather behind the waterfall and on Victoria from behind while spying Ashley and Brandon having sex, and later received a blowjob from her at the cave). Had a crush on Hannah when he was kid and before getting to know Victoria, he idolizes her. Used to date Lisa about eight months before the story and got dumped by her when she learned about his drunken escapade with an unknown girl during Ashley's birthday party, they had sex for the first time during the trip when Zack went to retrieve Gavin with Chloe at her cabin. As for other girls, Zack has been shown to have some level of admiration for Jennifer. He basically would be happy with having sex with either Heather or Victoria and would be a bit overwhelmed, but pleased nonetheless, about doing it with Hannah. He probably wouldn't mind doing it with Lisa again. Ashley and Chloe are two girls he had never really thought about sexually for different reasons (Brandon and old friendship). Incest with Taylor never crossed his mind either, but that's something that may change as the game progresses or when he sees her at the orgy. Kendra is someone he doesn't really know other than the fact that she was a friend of his sister during high school.
Gavin: The only virgin amongst the guys, fell in love with his old friend Chloe and had small crushes on Heather and Taylor at some point on his life. The only experience he has comes from watching porn and licking Chloe at Lisa's cabin, not to mention an unfinished handjob from Lisa herself at the same night. He probably would feel comfortable only with Chloe, but during the orgy, extreme horniness may change that.
Brandon: He only had sex with Ashley on his entire life, but their relationship seems to be hanging by a thread right now because of her. As for other girls, he used to lust for Victoria before meeting Ashley and falling in love with her, he also admitted on his thoughts to have jerked off to Ashley's sister Hannah a few times. He probably gave passing looks at Chloe or Heather a few rare times as well. He thinks that Ashley is the only girl in his mind, but the orgy might cause some of his repressed urges to be released.
Kurt: The most experienced amidst the boys. Admired Jennifer ever since he was a little boy on the summer camp. After he had his heart broken by a girl named Andrea, he turned into an uncaring jerk hellbent on fucking as many girls as possible without giving a damn about them; but Heather and Zack helped to redeem him later after his blunder with Chloe. He only had sex with girls of his own age group, which might enhance his curiosity towards Jennifer, an older woman. As for other girls, he lusts towards his cousin Heather, but he doesn't understand it (it might be some level of curiosity on breaking the taboo of fucking a family member). The unfinished photoshoot with Chloe in the woods might have some consequences here. All in all, he probably wouldn't mind having a go at any of the girls.
Peter: Never fully recovered from the break up with Hannah and still carries a torch for her, a fact that eventually ruined all of his subsequent relationships. He and Taylor are old friends (a bit like Zack and Chloe, but not so much), however the possibility of hooking up never crossed their minds before (that might change during the party). Probably wouldn't mind doing the other girls as long as it doesn't messes the chances he still thinks he has with Hannah.
Dustin: His sole focus on the trip is Victoria, he wants to have her back as his girlfriend, even if it means a long-distance relationship. Tried dating other girls and had sex with a couple of them, but it didn't work because his mind is focused on Vicky.
Shawn: Used to date Kendra back in high school, but now he uses her devotion to him to treat her as a sex slave. In his opinion, the only use girls have is to please his cock in any way he wants. Developed a fixation on fucking Victoria ever since she was dating his brother, he wanted to ruin her for him, to make him watch as he deflowered her. He also wants to screw Taylor because he thinks she looks down at him, a crime in his eyes since he sees all girls as cock-hungry sluts.
Heather: The most experienced amidst the younger girls. Had sex with three different boys, not counting her first time, when she drank too much and felt like a slut. Ever since they came into the cabin, she has been developing feelings for Zack, a change from the guys she usually dates, who only seem to want sex from her. Has been rediscovering a friendship with her cousin Kurt during the past half day. Kissed two different girls just for fun and wouldn't be opposed to doing it again or go further with one in the right circumstances.
Victoria: A virgin, has developed feelings for Zack after discovering their shared interest of mysteries and remembers fondly about Dustin, becoming really confused about her feelings when she saw him again just before the party. Never had any lesbian experience, and she'd probably be the hardest one to see interacting with a girl, since she's the straightest amongst the girls and isn't curious to do it (you never know what may happen in a truth or dare game or during an orgy, though).
Ashley: She only was with one guy in her life, Brandon. However, their relationship is suffering a deteriorating process, due to Ashley's increasing curiosity about being with a different boy (no matter each one, although she'd probably have a bigger interest on gentler guys, like Zack, Gavin or Peter). Never thought about girls sexually before, but she wouldn't be opposed to a little experimenting.
Chloe: A virgin, has been experiencing a few interesting moments during the trip, like the aborted photoshoot with Kurt and the time Gavin licked her to an orgasm after she spied on Zack fucking Lisa, a fact that made her take a romantic interest on Gavin. Her image issues could be a problem during an orgy, but she has been lowering her guard lately with people that make her feel at ease with herself and her body. Never had a lesbian experience, but she's comfortable with naked girls (the soccer team's locker room helping with that) and a little experimenting might not find too much resistance from her.
Taylor: Probably the most normal girl of them all, dated a few times during high school and college, had sex, doesn't have any hidden urge (nothing that she knows about, at least). Incest with Zack never crossed her mind, but that can change during an extreme situation. Never even kissed a girl, but she would be open to new experiences.
Hannah: The most experienced of the girls. Became bi after breaking up with Peter, dating and having sex with both guys and girls, nothing in excess though. Open to a little of everything, curious to experience new feelings.
Kendra: Loves and hates Shawn, the center of her universe. Hates the way he treats her, but she can't get away because she loves him. An extreme situation might be a way for her to fall deeper into her current predicament or to break free of the hold Shawn has on her.
Lisa: Still likes Zack, even after eight months of their break up. She promised to herself to get over him after they had sex at her cabin the night before. She would probably be a bit scared of trying new things, but it might be a way for her to fulfill her promise and forget Zack.
Jennifer: A 28-year old woman who doesn't have much time to herself, due to her hard work as a ranger, a fact that limits her dating opportunities. Because of that, she sees the party as a way to unwind for a while, although she would be very reluctant and wary of getting herself involved in a sexual way with kids that much younger than her (the game would play a big part into seducing her into participating in whatever madness happening later).
