>>528369590
>i keep completing missions only for them to fail because the npc dies to a dog or something
Are you sure you're not just running out of time? Most side quests in SoC have a 1 day time limit to turn them in.
I can't think of many NPCs in vanilla SoC who can be killed by a-life while you're doing their quests, they are usually standing in safe places, where they can't die easily.