Shortest solution to the problem (when is Prizrak killed in previous misson and you joined NAPA):
1) download the debugging console, install.
2) Start the mission
3) Open the console, execute this command
BIS_NPrizrak setPos [(position BIS_cooper select 0) - 1.5, (position BIS_cooper select 1) + 1.5, 0]
4) You will see Prizrak near you - kill him.
5) Now you can go to Marny and he will welcome you, your team will follow you...
There is one bug in the mission, when Prizrak was killed in previous mission, this mission move him only out of map, but he is still alive, thus one condition prevents continuing of the dialog flow, which enable again the "MOVE" command for your team mates and other triggers. I think that you can use this "workaround" even if you are playing the mission for some time...