they seem pretty imaginable to me in that official future sketch art of them in ch. 267.1 and in other official illustrations released on the author’s weibo with them kissing or being affectionate with each other but that’s just me ... ╮(￣▽￣)╭ personally it’s easy for me to imagine them as a couple or in sexual situations. I imagine them similar to other “protective stoic x bubbly-ish relationships” like li huan and yu yang from here u are and doumeki and yashiro from saezuru or the fanon tododeku couple from bnha or like the couple from cherry blossoms after winter... idk if those examples may help for you.
think for he tian and mo, it may seem easier since they have a lot more sexual undertones in their scenes within the actual storyline which therefore means it’s sorta already given to us and there is less to “imagine” since it’s handed on a silver platter if that makes sense. and they are the more“ typical flirty perv x extreme tsundere couple”, love them.. my faves. since those types are more common I doubt I have to give examples especially since they’re easy for you to visualize already.. but just as an honorable mention, they are super similar to my other faves: kiribaku, another fanon bnha ship lol espcially bakugo and mo ahhh!! ;) my fave scene of them recently is when he tian gave mo the earrings and mo was like “pfft they’re whatever” and yet immediately started wearing them the next day and has never taken them off since LOL.
He Tian and Mo have a more physical way of interacting.
Jian Yi and Zheng Xi communicate on a more emotional level.
They're both easy to imagine for me. One is the old married couple that have been together forever. The other is the couple just starting out.
For some reason I can't imagine Jian Yi and Zheng Xi ever being a couple (it's not yaoi, anyway) or doing dirty things.. Mo and He tian on the other hand.. (▰˘◡˘▰)