Mist and Shadows and Fade, as far as I can tell take part during the months leading up to the blight emerging. As for your characters, Simus, they'd probably end up fleeing the city with the few survivors of the attack. Unless, of course, you'd prefer they die not so glorious deaths in defending a doomed city. I'd guess Simus, Titus and Alice would probably join up with Skyrims military to defend the refugees, while Carlotta, Cilla and Mila joined the refugees and fled to whichever city they felt was safest.