It sounds like Marc and Kevin definitely know each other but probably never had a chance to get to know each other well, if that works for you? Marc didn't really get involved in the war until his brother got clean, somewhere around December 2017, but he was involved in raiding and supply scavenging before then as well. (Good to know! One day it should come up :|)
Yeah, I don't think that if Pikachu expressed any qualms about the whole scenario that he would have been allowed to opt out, sadly. So all of that stuff sounds good to me!