Unfortunately, no, you can't stay at stage three for very long, and stage 4 is what it is because NPC's are hostile. You could potentially mitigate the hostility by using "Calm" spells, although this wouldn't be practical in areas with many NPC's. Stage 3 lasts 24 hours; after that, you progress to stage 4.I'm not sure if you've read our guide on Vampirism or not, so I'll link it just in case my answer doesn't cover all of your questions. You should consider creating an account here. It comes with several benefits, and also makes it much easier for you to post questions and answers. It's completely free!