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For anyone looking to change race, you can sort of do so by combining the risky ver. of this mod with the origins plus mod, I've done full playthroughs with no issues with Astarion as a tiefling and other companions as other races as well. 

It doesn't change the body, only the head. It also does not change their race in dialogue or anywhere else. There's also sometimes seams on the necks. It does give them the racial abilities.

There are specific steps to get this to work though, so it might not be ideal for everyone. I use vortex.

1. Enable risky and origins plus, disable edit enhanced
2. Select companion, hide, enter the CC
3. Select the companion from the menu (If you edit a different companion than the one entered with it works but sometimes causes issues so avoid it.)
4. Change their race, be sure to select the same body type as theirs (For Lae'zel Bodytype 1 works)
5. Proceed and create a new save, then quit the game.
6. Enable Edit Enhanced, disable Risky and Origins Plus
7. Reload and enter the mirror, then click randomize once, and if done correctly you should be able to now customize them with the race specific heads.

This doesn't change gender, if you try it causes floating or sunken heads. However I've gotten it to work just fine with the gender swap mods. Doesn't work unless the body type is similar to the original body type. You can however edit the gender identity, this will cause NPCs to refer to you as the selected identity, helpful for gender swapped mods. I did a full playthough as female Astarion and NPCs referred to me as she.

Also, I gave Karlach dame Aylin's head and now and then her teeth glitched a bit, but otherwise it was fine. To hide her horns and tail you'll need a mod called half-tiefs.

Not a perfect solution but it's been fun to play around with. Just figured since I found this work around I'd share.

Edit: I posted some pics of changing Lae'zel on my profile if it helps