Oh well, I know it's kind of easy to use CC add-on for making morphs, but I never use it for that.
For morphs, I always use a direct import/export to/from Blender (and know by heart import/export settings) to avoid this kind of complications.

You cannot use the model you morphed for importing as a slider to CC in any way, unless you checked Keep Vertex Order and Polygroups on import to Blender (which I am sure you did not).
The only way to handle it now, is to transfer the shape to other model (correctly imported to Blender):  https://forum.reallusion.com/FindPost482754.aspx And I hope you exported the original model for morphing as OBJ in bind pose - body.

Now you have to mask a tongue (with mask modifier) for both, source and target model and transfer the shape. Look at the Video tut (second post at the thread above) and try it out.

In your case you'd need to transfer the shape for whole body, which is even easier.
If you do not have vertex groups for body and tongue for your originally imported model, you may even delete tongue all together from it.
Then only mask tongue using CC_Base_Body group on a target and use the same CC_Base_Body group for mesh transfer.
Let me know if you have questions, or stuck at some step.

Here is a routine for a full body transfer: https://forum.reallusion.com/FindPost493559.aspx

If you exported a full body, then you'd have 2 options:

1. Import neutral base (body only) for target. And then delete eyes, teeth, eye occlusion, eye tear line and tongue meshes from the original character.
Leaving only body, eyelashes and lacrimal. Then transfer body shape as shown in the video.
In CC you'd also have to tweak eyes and teeth bones for correct placement as shown.
Occlusion and tear line are optional meshes and easily added from modify panel with Enhance Eyes button.

If you had custom skin for the original character in CC, you may save it in Skin > Overall folder and reapply it, once you import morph slider to a neutral base.
Same goes to eyes and teeth, you may save them separately from original character in CC and reapply to morphed neutral base.

2. I just found this out and successfully tried it.
You may actually import a full body neutral base and successfully transfer "whole thing", including eyes, teeth, etc.
But here is a catch. You would have to spread UV tiles for both source and target avatars uniformly so that there is NO single UV overlap.

Here is my UV map after arrangement (must the the same for both avatars):

76% of original size (was 666x19) - Click to enlarge



To be on a safe side, I was also making sure to have right and left tiles for eyes, cornea, occlusions and tear lines do match between avatars.
Tiles location quadrants do not matter as long as there is a match between avatars.
Moving tiles is easy. Once respective tile/mesh is selected, use the following command:

G Y 1 moves 1 quadrant up
G Y -1 moves 1 quadrant down
G X 1 moves 1 quadrant to the right
G X -1 moves 1 quadrant to the left

That also means there is no need to mask a Tongue with modifier anymore for body only import. Moving a tongue tile 1 quadrant down for both avatars is sufficient enough for successful transfer.