Where to continue the Toilet-Bound Hanako-kun manga

Toilet-Bound Hanako-kun by AidaIro, 2014. The manga is still ongoing.

• Season 1 (12 episodes): Continue the manga from chapter 23 in volume 5. Season 1 jumps ahead after chapter 22 and adapts chapters 30 to 36 early, so read 23 to 29 and then skip to the second half of chapter 36.
• Season 2 Part 1 (12 episodes): Continue the manga from chapter 59 in volume 12.
• Season 2 Part 2 (12 episodes): Continue the manga from chapter 92 in volume 19. The finale skips chapter 89 and stops partway into chapter 92, so you'll re-read its first pages.