We load MC and on the first screen we load our newly created V4 character with the morphs. I had called her "Victoria 4 MCtest".

You will see all her actor and morphs shown in the list sorted by actor.
You will recognize a lot of "Empty" called entries. These are all dummies in the CR2 but not having real delta data in the moment. So these are useless for MC cause without information how to transfer them into a clothing.

You see the malebody morph which is standard build in with V4.2. This is complete and useable for MC. In the body section you hace a number of 51 behind this male morph. This is the indicator that this body dial is steering 51 other morph dial in all actors. So if you activate this here in body section all these other 51 morphs are included automatical into the process. NO need to activate this male morph in any other part.

But if you need only the male morph in abdomen to be transfered you can leave the body checkmark out and only activate in abdomen or ther needed.
But for these FBM's I strongly recommend to use only the body switch in total. Then you have nor need to search for all dependencies by yourself.

Even if your cloth isn't having all body parts you should do so cause by default MC is only transfering to given parts in the cloth.

Ok, you see following this rules we have activated onlyHelena body in the body section and NOT in abdomen or else.

And we have activated our AlienOnBoard in the abdomen section cause onlythere given and as you see it's a single morph. No dependencies are shown.