a. This show is too good to get a second season. only trash gets sequels.
b. If it does somehow get a second season, it will probably be about the future chapters of the couples already shown, and not introducing all the skipped over.
Maybe they can make a 20 minute OVA for the important introduction chapters of the characters they want to add to S2. You could probably cram in picrelated, Patty, karate-shota, and stoic-couple. Hopefully they don't add Yandere girl, rap boy, and the girl who likes the teacher, because they are shit.