linuxfreebird implemented a mod based on this research, you can use it here

<aside> ⚠️ Using these commands could unexpectedly break/trigger quests and other events during your playthrough. If you have specific questions, you can reach me @moxi on the dev channels on the Larian Discord Server.

</aside>

Terms I use:

Origin character: a player controlled character of one of the story characters. You don’t get to talk to them because you are them, and their romance kisses and cutscenes aren’t triggered. Their personal story may miss a few scenes and have extra other scenes.

Companion character: story characters as companions. You can talk to them, gain approval, see their cut scenes, romance them, and end up with them post game.

In my example, my origin character is a tav as Gale origin. I made Gale into a tav using mods for the roleplaying aspect, so I could get his story and bring Astarion to Elysium. However when I reached the epilogue, I was not given that option because I was on Gale origin! So I came up with a way to swap Gale to companion so I can trigger godgale’s epilogue scenes.

This method also enables kisses and group voiceline gossips for your Origin character, once they have been converted to companion.

My tav on Gale origin. Her name is Nightingale. My run includes Minthara, Sharan Shadowheart and Laezel on Orpheus path. I signed with Raphael to get the hammer so I can have him try to take it back.

https://lh7-us.googleusercontent.com/docsz/AD_4nXd11saGi0Hn1hbEt2au1azHH8qnxq-QQYJsQOIQfuDSG4EAaVWdvQZgev_pWEa5zKWTfZTNgAP7QAnJEDm-v3kts2TPPeZEI2o-QQyHyWmmwxz-lHzWSl9sx2o0oXaWgXxV_pBuFaOmcmG2fU_ZVVkDLik?key=JKguCSVX2Zh2fvI55A7q4A

The little Vampire Ascendant.

https://lh7-us.googleusercontent.com/docsz/AD_4nXctkzb96qsDgy3LEJoykcEenQT6NJneBF03olHluSAYzvtSYYpO0Z9blqWIefYxyq2auAIsY2No9pDOBN0QgGE6cNTfgRwguFw-kxOSa9_O7icTmUWOYmHwJ2pdc32zYL9yoD7XmN3qxuYzImx5CKGuWPs-?key=JKguCSVX2Zh2fvI55A7q4A