@CaprianaB - It’s
this one. It meant that the kids could have both an alien form and a human one, plus the mermaid tail. There may still have been times when the teens aged up with half their body missing but I think all I had to do was change the type of tail in CAS and it was right again.
Changing them to full mermaids was a built-in cheat. If you do Ctrl-Alt-C, then type in
testingcheats on, then type
traits.remove_trait trait_OccultAlien. That should leave just the mermaid traits behind. It’s been a while since I did this so hopefully that works. When they became simply mermaids, they kept whatever their human disguise was, not their alien skin, but that should be able to be fixed in CAS is you want lavender skin :)