All this implying we play as Hajime 

Chiaki: something similar to Kaede's Love Suite event, Hajime plays the role of her BF. Might have some spicy stuff but nothing actually lewd 

Fuyuhiko: Him confessing his feelings to his bodyguard, mostly emotional stuff.

Kazuichi: starts with Souda acting like a playboy but quickly turns into a fantasy of him bonding with someone who appreciates his true self 

Mahiru: Basic GF stuff, I can see her pulling a "do it with me" like Kaede but nothing more 

Sonia: Hajime would likely play some kind of former partner/lover role and feel completely lost in her fantasy forcing Sonia to do everything herself 

Pekoyama: dating her master, I can see her fantasy being more about the drama but it is possible she fantasizes about being intimate with Fuyuhiko (she is the one always reaching out for him after all)

Hiyoko: Having her way with someone inferior to her (physically or socially) something similar to Angie's fantasy 

Akane: she would definitely open with "Do whatever you want with my body!" Or something similar...

Teruteru: at the very least I hope he's better than Korekiyo...

Impostor: if we don't get a fantasy modeled after his togami persona I can see him fantasizing about showing his True self to someone he cares about.

Nidai: I'm expecting something similar to Ryoma's fantasy but with Nekomaru in the role of the Manager trying to help a struggling/depressed athlete.

Ibuki: Something batshit crazy and mostly comedic that ends with a small hint of romance 

Tanaka: Maybe something like Himiko's fantasy but instead of romance oriented it would be full on supernatural action, or something like a Shounen version of Kaito's fantasy.

Mikan: I'm expecting this one to Nuke the community if it ever happens... You should be able to guess why...

Komaeda: genuinely no idea. I'm sure he would fantasize about Hajime (same way Oma fantasizes about Shuichi) but it could go anywhere, wholesome, lewd, super sad and dramatic... Who knows?

If 2x2 ends up having Love Suite events this is what I expect for each character