Hi Rachel!
Welcome to the family. Since you've actually been here awhile you're like a lost relative I never knew I had. Glad you decided to say hi.
I spent three years in Japan, the toilets are like American ones. A little smaller, but pretty much the same thing. On the fancy ones there are buttons that do things (like spray clean water or blow air to dry you), those have pictures so they're pretty self-explanatory. Maybe I don't know about something fancy about toilets in Korea? I only ever went through the Korean airport, so I can't say anything about what it's like there. Seems nice though.
Make yourself at home. I hope you can find your answers.
love,
-maggie