There are extra pages for Natsumi, Touko and Souta too. When will someone TL them?
I put the Natsumi one into a Machine Translator and this is what I got.
Panel 1: Aha [あは]
Panel 2: You came to pick me up... [迎えに来て くれたんだ]
Panel 3: I'm home. [ただいま]
The extra pages with Futaba, Senpai, and the kids, said that Yuuto is with them and Natsumi's getting picked up at the airport so we're likely seeing Yuuto's POV here, and Natsumi's looking way up at the viewer, implying that after the time skip Yuuto is about the same height as senpai (maybe taller).
Either that or he's not showing who it is to make it deliberately ambiguous, so the viewer (and himself) could insert themselves as who she ends up with, which also explains the POV shot. If that's the case, he's such a loser.
The page with Yuuto's sister's wedding is just her boyfriend saying he's nervous and caught off guard. It might be a callback to something and I'm missing some nuances.
From what I've seen in these pages, Shiromanta is leaving it ambiguous whether the Sakurai-looking tomboy hanging out with Futaba's kid is Yuuto's kid, or Yuuto's sister's, presumably because he's a coward who doesn't want to acknowledge whether or not his self-indulgent brown waifu OC got together with a man. I hope I'm proven wrong when somebody releases a proper translation, but I don't have my hopes up.