You know, I don't really see many comments about Wes, so I'm glad you find him intriguing. You'll have chances to spend time with all the dorm guys in some fashion, though most likely not one-on-one like the main characters.
You're in luck in regard to Trevor. There's a new feature coming soon that lets you unlock fantasy hookups with some side characters, with a new one coming between each story update. Trevor was just voted to be the second guy to get a hookup, so that'll be unlockable in a future update.
For that CG, dominozz has it right, but there's one additional requirement to unlock it. You need to spend your time after Alex's presentation with Griffin, then after the Skinema show choose to go dance solo or with Isaiah. Once you go downstairs, that CG will unlock.