The sonar is incredibly op and since you can tell which kid it is based off of the outline, if they transform or use the bookshelf, you can see it and tell everyone. This makes secret neighbor not so secret, and so does the next point
Kids can very easily tell when the neighbor killed someone based off of the saturation and ambience, its very op and maybe only desaturate and play the heavy ambience when the basements open, or fade it in as the time runs out