#C, 173 bytes
Pass a NULL-terminated array of strings to f(), and it will print out the missing names.
*a[]={"Blinky","Inky","Pinky","Clyde",0},**s,**r,n;f(int**p){for(r=p;*p;)strcmp(*p++,"Pac-Man")&&r=a+4;for(s=a;*s;++s){for(p=r,n=0;!n&&*p;++p)n=!strcmp(*s,*p);n||puts(*s);}}