Ravenous Bugblatter Beast of Traal
Just to build on what you were saying, there also seems to be the "ethical" points that Pietro brought up - there's been no outside children until this episode, so she must have been keeping them asleep until now regardless of how close/fare they were. (He also mentioned for the most part couples staying together.)So, this seems consistent with what we see:
The closer you are to Wanda, the more active you are - the farther folks are from Wanda (or perhaps more accurately, the less involved people are in the action of the "sitcom"), the more they become like lawn ornaments.
The more active you are in the Hex, the more aware you are. Vision and Peitro are very close to Wanda, so they have more awareness and free will. Agnes became less aware the farther she was from the center of the action.