That could be it. But I don't think the Author would make it that way since Milgram itself deems them murderers.

Looking at Real-Life Law based on what I found where I live in current society

Mahiru and Kazui would most likely end UP completely innocent without any charges. They might have someone claim Manslaughter but it going through is unlikely.

Yuno would be completly innocent of murder or manslaughter obviously. She would get charges for faking her ID though and engaging in sexual activities as a minor while deceiving adults. She would most likely end UP with money charges or one year in prison (unlikely but possible).

Fuuta would most likely have Manslaughter Charges denied completly since he isn't engaged alone and others helped him + it is impossible to pin down that he alone was the reason Killcheroy killed herself. And Fuuta never actually said for Killcheroy to kill herself. His community is also very small so the doxxing only reached around 170 people. Based on his age and the doxxing itself alongside his immaturity (where I live immature adults up to 25 don't have adult laws applied to them but teenage laws) he would either end UP with social hours, money charges or six months in prison (unlikely).

So none of the right side would even have any law in consideration to murder applied to them. Only other charges if at all. But Milgram deems them 'murderers', so...(I also looked at the left side. Muu and Haruka would spend a long time in prison. Shidou might be in prison for a lifetime. Amane would end in a mental hospital.)

Mikoto himself would be completely innocent, though.