How does the Reaper and the WW move in the City?
I guess they can't walk into a shop and land on a character if they don't move the full distance on the movement roll. The rules mentions that characters can do this, but the NPC:s are no characters so…
On the other hand, if they are not characters can they walk against the arrows? It's also mentioned that characters can not do this, but still they are not characters.
That's a difficult question and deserves an official clarification, but I'll try to answer according to my personal opinions.
Reaper and Werewolf always move like characters. They do not violate movement rules doing what characters cannot. They do move like characters with increased freedom (freely cross Sentinel Bridge and Tavern Ferry, choose a space in any Region when teleporting out from Treasure Chamber, and Eyrie also), but they never do "illegal moves". Moreover, they cannot enter the Inner Region by any means (Rulesheet says no Portal of Power crossing and FAQ says no teleporting; what is said for Reaper applies to Werewolf as well).
A character can move into a shop and end his movement there, therefore the Reaper and Werewolf may do the same. The NPCs may not move against the arrows, because characters cannot. Characters can't enter the Jail Space normally and the NPCs can't as well; but they can be sent to a character on the Jail space if a 5 is rolled on the Reaper or Werewolf charts.
This means that sending the Reaper or the Werewolf following another character's footstep is a good move, as the NPC may follow the character in each shop they want to visit and pose a constant threat. Unless he's lucky enough to roll a couple of 1s and make the pursuing NPC walk past him.