This answer may come too late for you but I have also been learning to import characters using Affinity Designer and the Human Templates from Reallusion. I have found that if you select a Pivot point the whole group is selected, as you stated. If you double click, or sometimes triple click you can select just the one Pivot point. I have found that zooming into the pivot point often helps is selecting the points.
Also, sometimes when parts don't import into CTA I have found I need to go back into AD and check the name of the layer very carefully. Sometimes when copying and pasting layers AD will add "Layer" to the name. Each layer will always Show the name of the layer and next to that tell you what type of layer it is. But you need to check if the type of layer is actually part of the layer name. For instance
RightBrow (Layer) in this case (layer) is not part of the name "RightBrow"
But sometimes the layer is renamed "RightBrow (Layer)" (layer)   This will not import into CTA

Also you need to be aware of any sub layer names in groups, such as for the eyes.

ALMOST every time a body part or parts does not import, it is because of a misnaming.

I had the same error issues after switching from Photoshop to Affinity.

I discovered that deleting the 'RL_TalkingHead' group from Human_Front_Full_Template resolved the errors. It didn't matter whether I used Affinity Photo or Designer. 
G

You need to use this file. It was sent to me by the devs... Just make your layers and then insert them into the correct group, but delete the other layers just before you do that. It works

 http://ftp.reallusion.com.tw/reallusionsupport/163761/Human_Actor_Fixed.psd

http://ftp.reallusion.com.tw/reallusionsupport/163761/Solution.mp4

Is it still possible to get the file somewhere? The given links don't work anymore.

You can contact Customer Support using the link below. They should be able to supply you with those files.

https://www.reallusion.com/CustomerSupport/UserEx/QForm.html


                                                                

Peter
Forum Administrator

www.reallusion.com