Just a quick outline for those who are reading SMK: Growing Up and haven't read SMK. There's also some info that I never explicitly stated. This is also for me to keep things straight.

Adults

Yifan&Yixing

By the beginning of SMKGU, they're 28&29, and they've been engaged for over 1 year, together for 6. They first met at one of Yixing's gig. Love ensued. Now they have Zitao.

Yifan is a commercial model; he's not super famous so his work is usually limited to advertisements and small fashion shows. He's been married previously to his childhood friend, Junmyeon for a short time. They realized they weren't in love with each other and parted ways. Both the prequel and sequel lean toward being Yifan-centered.

Yixing is in an indie band as the guitarist/composer. He has a replacement guitarist he switches out with (which explains why he's home so much).

Chanyeol&Baekhyun&Junmyeon

By the beginning of SMKGU, Chanyeol&Baekhyun are 23/24 and Junmyeon is 28.

Chanyeol is a commercial model along with Yifan, which is how they came to be good friends. He met Baekhyun when he was a teenager, which almost immediately resulted in Kyungsoo. He got involved with some unfavorable people and started doing unfavorable things and this caused Baekhyun to break up with him and stop talking to him until Kyungsoo was 14 months. Because of his guilt for missing the first year of his son's life, he's dedicated to being a good father even though he's still hurt at not still being with Baekhyun.

Baekhyun actually works at Krisyeol's modeling agency as a desk worker (taking calls, setting up appointments, not exciting work), which is what forced him to start speaking to Chanyeol again. He was signed to a contract at the modeling agency, but then Kyungsoo happened so he quit and moved back home with his parents for a while (the 14 months he raised Kyungsoo alone). He met his husband, Junmyeon, at a bar and they married QUICKLY. He's kinda friends with Yifan but is much closer with Yixing. He's still very much in love with Chanyeol, but he believes that once a relationship is done, it's done.

Junmyeon (my poor baby) has been married to Baekhyun for a little over a year. He was married to Yifan for a short while, as you know, but as of the beginning of SMKGU, he hasn't told Baekhyun. He works two jobs, which is why he's almost MIA. During the day, he works at a men's clothing store and at night he bartends (at the same bar he met Baekhyun). When he's not working, he's most likely sleeping.

Kids:

Zitao

Our bratty little star.

Minseok&Luhan

By the beginning of SMKGU, they're 6 going on 7. Luhan lives next door to Fanxing, while Minseok lives next door to Luhan (that explains why they're at Fanxing's house so much).

Basically, they're the mini version of real life Xiuhan. Luhan absolutely loves Minseok (he proposed with a toy ring when they were 5) and wants him completely to himself. His overprotectiveness has him sometimes being mean to whoever he believes to be a threat (i.e. Kyungsoo). He's mischievious, but nowhere as bratty as Zitao.

Minseok does his best to level Luhan out. He really likes Luhan too but isn't so gong ho about it. He goes along with all of Luhan's love confessions, but as most normal 6/7 year olds, he has no real interest in who he's going to marry as an adult. He's recently a big brother.

Kyungsoo

By the beginning of SMKGU, he's just turned 5.

Kyungsoo is Chanbaek's son. He comes off very shy and innocent at first, but he's aware of his image and uses it to his advantage. He splits his time between Chanyeol's and Subaek's apartments. When both his parents are tied up, he stays with Fanxing and plays with Xiuhan.