-Usami going into details of what happened to her family, basically she's been abandoned by her parents and they no longer care about her; enough to pay for her tuition, living costs and such, but otherwise she's 'persona non grata'. Usami says it's alright though, since she now has friends and Jiro, so she's not lonely anymore.
-Kanade weaponized 'derechuki' as a method to grab Jiro's heart. It's super effective
Kanade also revealed Usami lost her ability to 100% tell truth from lies; Usami's ability stemmed from not trusting anyone, but now that she has friends and is happy she can't do that anymore. Proof is when Kanade said she's going out with Subaru, and Usami believed it.
-Subaru went with Jiro, at a nighttime 'date' gazing at the stars, on the final night of the holidays. Jiro grabbed Subaru and embraced her, asking to stay like that for a while longer. Half a hour later, he confessed to Subaru one more time, this time resolving if Subaru rejected him again he'll finally give up. Subaru returned his feelings, checking if he's really cured of his gynophobia, and upon kissing him to check it turns out Jiro's completely cured.
(final bombshell at the end of volume omitted, not enough time to type it all out right now)