Can we raid settlements that have essential characters and kill those essential characters? or are those characters just staying there shooting forever or just strangely absent?There's actually some 'hired guns' NPCs spawning to defend the settlement, probably to prevent what you just said. So, it's hired guns and whatever settler in the town versus you and raiders.
Thanks for the information you provided by the way seems like it is just more of the same, Bethesda being Bethesda... I fear for the next Beth games... no way I am buying them unless Bethesda changes it's games direction 180º.