A lot of those names seem fairly positive. That's appropriate if your intent is that people generally like them. If they are a little iffy, I think focusing on the silence part is more appropriate than the mental part -- name them based on perceived flaws rather than strengths. From the description, they seem mute, simple (in the negative sense), primitive. Madmutes, starkers (which has a double meaning about madness and nudity).
If people regard them with suspicion or negative, could be named based on those strengths but in a negative light, names about what people fear. Overseer, enthraller, imperious, brainsick.