they do indeed seem loony. i have experience of this also, to the extent of using setdir to position characters at *precisely* the right angle to face the player, and yet about 20% of the time after a dowatch command they still turn away from the player. i'm afraid this seems peculiar to opf.
you could use the disableai "move" command, which keeps loons rooted to the spot, or disableai "autotarget", which stops them choosing a new target if one happens to walk through your cutscene, but otherwise i think that's as far as the control goes, unless you want to set up a looping script which setdirs your characters at a certain angle throughout the cutscene...
hope this helps
bedges