You can already use CrazyTalk 8 3D heads in CC3.
1. In CrazyTalk 8 just export your 3D head as an RLHead
2. In CC3 load a CC1 Base Character from the folder shown in the image below.
3. Now on the Morphs tab of the Modify Panel select "Head" from the left column and then click "Reset" at the bottom of the right column.
3. Now drag your exported CT8 RLHead onto your CC1 character in CC3 and it will apply as normal.
4. You can now optionally convert the CC1 character to a CC3 character if you wish.