Professions:

Woohyun owns a cafe named Coffee Tree.
Myungsoo works as a musician and waiter for Coffee Tree, and also goes to school for photography.
Hoya is a dance instructor, and also goes to school for dance.
Dongwoo works with Hoya, studies fashion, and is an intern at a designing company.
Sunggyu works as the manager of a bank, and was trained originally as an account.
Sungjong is still in school, a college freshman, studying music.
Sungyeol is also still in school, studying literature and is currently a journalist.

Relationships:

MyungJong - obviously VERY intimate and all. They love and appreciate each other and... just MyungJong, guys!! 

WooGyu - complicated really. Sunggyu takes care of all the taxes and stuff for Woohyun's cafe and gives him business tips. They're currently dating, having every so often but not as weird or often as Myungsoo and Sungjong.

YaDong - just really close friends. They're very fond of each other and they like to joke around and have similar interests, but they have no interest in dating each other. 

MyungYeol - mostly like YaDong. They're close friends, joke with each other;  Sungyeol helps Myungsoo a lot whenever he and Sungjong get into fights. 

HoJong - Hoya ends up being a very super protective older brother of Sungjong. He doesn't see Sungjong romantically at all, just a boy who needs to be protected; while Sungjong thinks of himself as a man and sometimes wishes Hoya would recognize that he's grown up, but appreciates how much he cares.

GyuJong - Sunggyu also sees himself as Sungjong's older brother who is very protective, but is more lenient as he realizes that Sungjong can take care of himself, but he keeps a close but silent eye on him and Myungsoo. He's very strict with both Myungsoo and Sungjong, but more so with Sungjong.

WooJong - He acts like Sungjong's brother who shows him how to charm and woo people. Sungjong and Woohyung enjoy each other's company, but at the end of the day, they're nothing more than friends. Woohyun likes to make strawberry-lemon smoothies for Sungjong or bring him lemon candies.

YeolJong - They're actually very fond of each other, but sometimes Sungjong gets incredibly insecure because Sungyeol had been in school longest and seems to be the smartest, and sometimes that intimidates Sungjong, but Sungyeol is kind and understanding with Sungjong, always encouraging him to push himself to the limit.

DongJong (lolz that sounds funny and probably isn't even the ship name) - Dongwoo is the fun uncle brother who takes Sungjong to the park whenever he wants to or things like that. Sungjong admires how Dongwoo is always smiling and aspires to be just as happy.

MyungGyu (lolz :P) - Sunggyu is very wary of Myungsoo because he knows that he's sensitive, though he doesn't show it. They don't interact often, but Myungsoo knows that Sunggyu is always there for him, so if Sunggyu ever asks for a favor, he usually never refuses to help.

Woohyun/Myungsoo (because I don't wanna butcher names any further ><) - Myungsoo actually is very guarded around Woohyun when Sungjong is involved, but between the two, they're nothing alike. Myungsoo is softspoken while Woohyun is very loud and active. Sometimes Myungsoo wishes Woohyun would stop involving Sungjong in clubbing or teaching him odd aegyo, but he says nothing about it to Sungjong.

Dongwoo/Myungsoo - Myungsoo, like Sungjong, admires how Dongwoo can always smile and goes to him whenever he's feeling down. Dongwoo, in return, always tries to make Myungsoo laugh and comes up with new jokes to amuse him.

Hoya/Myungsoo - Myungsoo really thinks that Hoya is an amazing dancer, and he appreciates when he takes care of Sungjong; however, the overprotectiveness gets on Myungsoo's nerves and sometimes wishes Hoya would back off. Hoya keeps a close eye on Myungsoo, making sure he doesn't hurt Sungjong.

(umm... I'm gonna stop there because this is a MyungJong-centric au, but if you have any questions of any other pairings, I can tell you how they fit in with the au. Anyways, thanks for reading this!! <3 *^^* Hope that enlightens a bit about the fic series~)