I understand you perfectly. That's why I want to share the way I use it.
1. First, you need to find a scene with facial animations about the same time as the KosoruCG scene, so that it looks the best.
2. Select the character from which we want to save the animation and delete everything in it that does not relate to facial expressions. These are various movements of the nodes of the shoulders, neck, buttocks, etc. Also, do not forget to check if there are any camera settings and time settings.
As a result, we are left with only facial expressions and nothing more.
3. It is necessary to save the facial expressions in a Single File. To do this, in the TimeLine window, click the appropriate name button for convenience and click "Save/Overwrite".
4. Next, load the KosoruCG scene or any other. We select a character and delete BS (eyebrows, mouth, teeth) and other parameters related to the face in the TimeLine.
5. For the selected character, go to KKPE "Advance bone" and go to the BlendShape section and click on the "Reset All" button
6. After that, you need to go back to the TimeLine with the selected character and save the SingleFile as in point 3.
7. As soon as we have saved 2 singlefiles, we load the necessary facial expressions that we saved the first time. In the same save menu, select the first option and click upload.
PAY ATTENTION! What you need to load is by the 2nd SingleFile that was saved earlier, since these files contain the original pose in which the original animation was created. In 99% of cases, the poses will be different and your character will be deformed.
Voila! You've transferred the character's facial expressions from one scene to another.
By the way, this way you can treat the breakdown of facial animation when you change the original author's card to your own and you have different types of heads. For example, the "Turime Face" may not inherit part of the animations or may not be displayed at all because the author's character had a "Modified headmod"
In general, this is not all that can be done with these files, but there is too much to paint. I hope I've helped you in some way.