You can't see through non-transparent bricks.
Yes, but you can use math and etc to narrow down the possible selections before raycasting. If there is only one gaze brick on the server, you would first find all the players within the operating radius, then find the fov of all the players in the radius, then find out if that one gaze brick is possibly in the user's sight. Then, shoot a raycast from player to brick or brick to player. If it hits the player/brick, the event is triggered.
If there are more than one gaze bricks, let's say very close together, you can use a little more math. Let's also say that there is a big 1x5x12 obscuring half of the gaze bricks from your view. Fire a single raycast that hits the wall. Now you get the dimensions of the wall, and figure out if more raycasts would hit that same brick, without actually firing any.
Poll