My friend Fado made a rough timeline of KaraFami, and with his permission, I'm archiving it here as well. I've edited a few things from their original document since I'll be focusing on the manga timeline. I consider the anime/movie to be a separate/alternate timeline from the manga, so I won't be listing the dates from there in this list. Again, feel free to reference the original document for the anime dates.
I'll be listing page numbers when relevant, based off the JP tankobons. I'll add the dates for Fami Vol.2 chapters when i receive my copy.
1980 (pre-canon)
May 5 - Kyouji is born. [ch.2.5, pg.]
May 15 - The kanji in Kyouji’s name are rewritten from 京二 (Second son) to 狂児 (Child of Madness) [ch.2.5, pg.]
2000 (pre-canon)
??? - Kyouji joins the yakuza. [ch.2.5, pg.136]
2005 (pre-canon)
*April 1 - Satomi is born. [seen in bonus]
2019
June 16 - Satomi's choir concert and their first meeting. [ch.1, pg.5]
June 18, 21, 25, 28 / July 2, 5, 9, 12, 16, 19, 23, 26, 30 - Approximate dates of their karaoke meetings. [pg.28] - “Every week on Tuesday and Friday […] Kyouji Narita made off with me…”
July 30 - Last day of karaoke. [pg.75] - “There were only two weeks left until August 11”
August 10 - Satomi goes to give Kyouji the omamori. [ch.2, pg.78]
August 11 - Karaoke contest/choir festival. [pg.93]
2023
Mid-to-late March - Satomi (17) graduates high school, finds Kyouji’s business card. [pg.123] Later in the month, meets Kyouji at the airport [pg.127]
April 1 - Satomi's 18th birthday, entrance ceremony at Rissho U. [not seen on-screen, referenced on pg.]
2023
April 14 - Satomi starts working at the Famires. [ch.0, date shown on pg.3]
May 27 - Satomi tells Kyouji about his present over breakfast. [ch.3, pg.57]
June 18-19 - Masanori thing [ch.4 - pg.100]. Chinese food date [ch.5], Muromachi Concert, Satomi is given Kyouji's watch and then boils it that night/early morning. [ch.6]
June 20 - Masanori and Kyouji get dinner [ch.7, pg.148], Makoto talks with Okada and informs Masanori; Masanori shows Kyouji the picture of him and Satomi. Off-screen, Kyouji decides to ghost Satomi.
Summer vacation - Satomi returns to Osaka and sees Wada at the Takoyaki Expo. [ch.9.5, not in vol 1]
October 6 - No word from Kyouji in 4 months ): Satomi saves up 113,500 yen. Sees Kyouji at the restaurant that night [ch.8, pg.154]
November 11 - Day: Okada gives his card to Satomi right after his shift [ch.9, pg.170] / Night: Yakiniku breakup, POST-YAKINIKU HUG DISASTER.
November 12-14 - Post-Yakiniku Hug Suffering, Mana + Yahoo answers advice. [ch.10]
November 22 - Kyouji visits Kumicho and the cats. [ch.11]
November 23 - Day: Personal uber eats guy [ch.12], Kumicho and Masanori reunite. [ch.13] / Night: Karaoke contest, Satomi ‘confirms’ something [ch.14], Kyouji & crew intimidate Okada. [ch.15-16]
November 24 - Donuts with Mana and Maruyama, "I like Kyouji. And Kyouji is alive. That's all there is to it." [ch.17]
December 15 - Satomi is accosted by Junko and Suzuki outside his apartment. Masanori’s ‘deadline’ is tomorrow. [ch.18]
December 22 - Masanori’s ‘actual deadline’. Goes to the famiresu to work. [ch.19]
December 23 - Day: Masanori wakes up to Suzuki extending his deadline to the 24th. Satomi tells Morita about Masanori, then returns to Osaka that afternoon [ch.19] / Night: Junko works the snack bar Christmas party, but sees an issue of Baum with her manga on the cover [ch.19]. She decides to go find Masanori and brings Okada along to help out on the manga. [ch.20]
??? - Back in Osaka, Satomi texts Kyouji and asks if he’d like to eat dinner tomorrow. He tells his parents he’ll definitely come home that night. [ch.21]
December 24 - Night: Sushi date. Kyouji talks about the only time he thought his father was cute. Kyouji offers to drive Satomi home when it gets late, but Satomi asks to take a walk. Money goes in river. They go to a famiresu… [ch.21]
December 25 - Day: …and stay out all night. Kyouji gives Satomi a half-hug when prompted, and they part at dawn. [ch.21]