I FINALLY found a fix that actually worked for me!!! I'll post this in a related thread I've got going so more people can find this solution.

None of the other fixes involving changing deltas worked for me. Here's what I did: in the Public Documents > My DAZ 3D Library > Runtime > Libraries > !DAZ > Victoria 4 > Head folder of the DAZ-installed V4 and Morphs++ , where the two share a common Runtime so the Morphforms work correctly... but in my case V4's eyes won't open or close, I noticed NINE files in the Head folder -- not FIVE like the normal V4 Head folder has and where the eyes open and close as they should. So I deleted the NINE files and replaced them by copying the FIVE files to the Head folder. Then I launched Poser and loaded V 4.2 to see what would happen. V4 wouldn't load and Poser informed me there was a missing file required, and it's name: 05-ps_pe070_DAZ_Chnnls.pz2. So I found that file out of the group of NINE I had previously deleted, added it to the FIVE I replaced the NINE files with, ran the DZ .bat file to initialize everything before launching Poser, AND THIS TIME WHEN I LOADED V4 THE EYES ACTUALLY WORKED!!!

Apparently, when you have the DAZ Installer merge V4 and Morphs++ into a shared Runtime, it adds some extra files in the Head folder which creates a conflict that breaks the V4 eye open-close parameter dial adjustment. But if you remove those files and replace them with just the FIVE files that are found in the V4 Runtime > Libraries > !DAZ > Victoria 4 > Head folder of an installation where it ISN'T merged with a M++ Runtime, plus return the 05-ps_pe070_DAZ_Chnnls.pz2 file found in Head folder of the DAZ-combined V4/M++ merged Runtime, that fixes the problem... At least on my platform... There is a chance I may in time find this fix has created other problems, but they can only be head-related since that's the only folder I modified. But Poser seemed happy once I added that sixth file (05-ps_pe070_DAZ_Chnnls.pz2).

Okay -- I did find a few problems and if I check out some more of those original NINE files there may be one or two more to add back some time later when I have the time... but they aren't showstoppers for me so far. Once you load Morphs++ to V4 there are a few head-related anomalies: The Morph++ parameter dials for Head Size is comical -- only the eyes and teeth enlarge. But yo can easily change the scale of the head directly using the Scale editing tool mouse pointer. The neck works okay. With the Full Body morph dials, the head doesn't change along with the rest of the body. In the coming days or weeks I'll look at the other Head folder files I removed to which ones I might need after all...