Is it asking a lot to know what you have to do to make expression (and Pose) morphs not affect a character? I actually once went back to a base V4++ to create some poses and expressions for my other characters based on V4 to use. All I wound up doing is setting my other characters to the V4++ with my expressions/Poses.  Also, I have a great set of Freebie Pixieluna (I forget - expressions or Poses and whether V3 or V4) that were probably early versions but wind of changing the character's appearance.

Oooh, sorry. I didn't see your question and the notify bots don't work. I don't socialize much in Poserverse these days, so don't often look at the fourms. 
Really there is no easy way to modify expressions so they don't affect the morphs.  You have to edit.  You can do this one of two ways that I'm aware of edit each .fc2 file (in a good text editing app) to take out the morph dial references. Or create a "stripped" .Cr2 where you remove all the face dials except the ones related to expressions and use that .cr2 to save expressions. You can use a free utility called Morph Manager to make a stripped .cr2 (don't overwrite your main figure .cr2).

http://www.morphography.uk.vu/dlutility.html

There may be an easier, less time-consuming way, but I'm not sure. Maybe one of the "under-the-hood" Poser gurus can help you there. Sorry.