It's hard to say for sure. Without specific information about 'Madu', it's difficult to determine if it's completely true. Maybe it's inspired by real life but with some creative liberties taken.
I'm not entirely sure which specific 'lagu ost new gisaeng story' you are referring to. It could be an OST (Original Sound Track) related to a new adaptation of the 'Gisaeng' story. Maybe it's from a drama or a musical. Without more context, it's difficult to provide detailed information.
I'm not sure where you can specifically find it. You could try searching on major music platforms like Spotify, Apple Music, or YouTube. Maybe search for it using the full name 'lagu ost new gisaeng story' and see if it pops up.
Sorry, I'm not very familiar with the specific 'ulala session love fiction' song lyrics. You can try to search for it on music platforms where you might find detailed lyrics explanations.
You could also check on social media platforms. There might be fan pages or groups dedicated to 'ulala session' where fans share and discuss things related to the band, including the lyrics of 'love fiction'. Additionally, YouTube music videos of the song may have the lyrics in the description or as captions, which can be a convenient way to access them.