Hello Firefab, thank you for liking my game!
You're right, the season 2 download contains all the updates (chapters 12 and 13).
Season 1 saves don't work with season 2 but your game choices will be migrated automatically if you played until the last scene of season 1.
I'll try to add more anal content, thanks for your suggestion!
You can also support me on patreon and get access to the monthly releases and other content.