19: Chase After Fukumen's True Identity; 20: I Want a Flower On the Stage
This was is in the credit page too, but here's a sort of outline of how the final volume played out.
Chapter 22 — Establish future plans, while feeling like they're steadily moving forward as they've advanced a school year.
Chapter 23 — Future of the cat cafe club is discussed.
Chapter 24 — Future of the cat cafe club is secured.
Chapter 25 — Wrap up of loose end of Disciplinary Committee guy liking Higurashi. Fukami-kun gets jelly, showing extent of his feelings. Also side ship.
Chapter 26 — Akio-chan gets jelly, showing extent of her feelings.
Chapter 27 — Meet the in-laws, Fukami family version. Resolve some of Fukami-kun's issues with family to a degree (mostly resolved by him changing, really).
Chapter 28 — Meet the in-laws, Higurashi family version part 1. Show Akio-chan's reasons for wanting to be a vet.
Chapter 29 — Meet the in-laws, Higurashi family version part 2. Akio-chan's issues with mom resolved.
Pretty much all loose ends wrapped up at this point, I think?
Chapter 30 — Slightly dramatic penultimate chapter showing how Fukami-kun has changed.
Chapter 31 — Final chapter showing how they've both changed, especially Akio-chan. Another side ship also confirmed.
And here's a version of the page I colored without text, if you're interested.