[2022] Everyone dead but the slaves. Can I continue with their story?

Long story short, my colonists thought they could take on an Ancient Giant Spider and his brood. They ended up dissolving in spider cocoons while their slaves Iggy and Blue Hair survived in the safety of the kitchen having a good laugh. Officially, they are still slaves - but they are clearly free (except for moi). They would like to f*ck off (Ancient Giant Spider plus brood is still around), maybe grab a few things and find a nice tile somewhere where nobody knows them. They just "rebelled" and are moving out. But I can't control them. Anyway I can make them into regular colonists and continue the story? I have character editor installed but can't see an option anywhere to convert slaves into colonists. Same with the development mode.