I don’t have problem with Mermaids and Vampires. If I go to the Cantina for freshen up this need goes up. Mermaids don’t need to be in water. Mermaids don’t loose the form in Sims 4 if you stay away from water. This feature is only in Sims 3.
Only Issues here is with the Powers(Child of the Moon/Dampend Emotions works fine) and Occult-Form. If you go with your Occult Sims to Baatu your sims are a “normal Sims” (Vlad don’t burn to dead in the Sun although he has thin Skinned 3 and no sun resistence) I don’t know is this by design or really a bug .
I play without Mods and never use it in this save.
