I can’t figure out how to do this with that addon. Tested with a druid in an instance. I can make their name white, illegible dark blue, or the default light blue.
I’ll have to examine the code more to figure out how they are even getting those colors because I am unable to call SetTextColor on ForbiddenNamePlates.
The latest version of Plater (550.2) has restored this functionality for me. It seems addons are now able to manually set the hideCastbar and hideHealthbar settings now.
Oh yeah, my bad. I just noticed that when I was toggling stuff the friendly NPCs in Vault switched from green to white and then saw the class color setting and mistook the two.