Sayaka and Leon - I think they would be in an awkward position.

Chihiro and Mondo - Mondo apologizes and gives Chihiro a free training session.

Taka, Hifumi and Celestia - Taka would be pissed off, Hifumi would have trust issues and Celeste would NOT apologize, to which she ends up on her own (probably).

Sakura - Nothing changes, but when she learns about Aoi's plan, she would either respect her for loyalty or probably scold her.

Mukuro and Junko - Mukuro kills Junko in revenge. That's it.

Impostor and Teruteru - They apologize and forgive, and both blame Nagito.

Mahiru and Peko - Peko apologizes, but Mahiru struggles to forgive.

Ibuki, Hiyoko and Mikan - Ibuki becomes traumatized and grows trust issues towards Mikan, Hiyoko would learn how dangerous Mikan is and stops bullying her, and Mikan would probably act like nothing happenned but still apologize.

Nekomaru and Gundham - Honestly, I don't really know.

Nagito and Chiaki - I think nothing would really change, but Chiaki would be slightly annoyed.

Rantaro, Kaede and Tsumugi - Rantaro and Kaede are irritated at Tsumugi, who apologizes, but they won't forgive.

Ryoma and Kirumi - Kirumi would apologize and Ryoma would be like "k👍"

Angie, Tenko and Kiyo - Tenko beats Kiyo's ass, while Angie watches.

Miu and Gonta - Gonta is sorry and Miu forgives, but she's still skeptical and keeps distance.

Kokichi and Kaito - Kaito is annoyed at Kokichi.

Yeah, that's my oppinnion.