#C, 135 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(s=a,r=p;*s;++s){for(p=r,n=0;!n&&*p;++p)n=!strcmp(*s,*p);n||puts(*s);}}
It doesn't yet work for the Pac-Man input, though. I'm still working on it.