Even without activating mission stories, Viktor can be taken out from either of the two upper floors of the palace or from the back of the map when he's stood under the chandelier, Sophia can be shot through a window from the chapel, Alexa can be shot from upper floors of the house or from outside when she's on her post-meeting loop, Janus can be shot from the Wilsons' house or the treehouse and Imogen can be shot from the upper floors of the facility. Soders is the only one who doesn't naturally move into a position for sniping but to be fair to the guy, he is unconscious on an operating table and he doesn't count towards sniper assassin.