Always fun! I jotted a few things down that you mentioned:
* Christmas is definitely more couples-oriented in Korea! I like that Sunwoo's mom points out that it's a relatively new development in her lifetime, especially the gift-giving and Santa-lore aspects.
* When the delivery guy unloads plastic-wrapped hot food dishes-- that definitely still happens to my knowledge! I should call my relatives and ask, lol. But I was fortunate to have a short internship in Seoul in 2007, and while there we got hot meals delievered *directly to our desks* by the excellent delivery guys on mopeds. We'd stack up the empty plates and bowls and they'd be gone an hour or two later.
*The young, pretty starlet Lee Miyeon has been mentioned a few times by male characters watching TV. This is a prettty funny 4th-wall breaking joke, since Lee Miyeon was not only a real person on 1988 television, but she grew up to play adult Deoksoon in Reply 1988, lol. All the funnier when they compare her to Hyeri's young Deoksoon character.
*Finally, the stone pots outside probably have fermenting bean paste and kimchi in them. Though I admit I don't know much about that side of things-- sorry, grandma, if you're listening! The area where you store these pots throughout the various seasons outdoors is called a jangdokdae (https://koreatourinformation.com/blog/2013/12/06/the-wonders-of-the-jangdokdae/)