Yes you can, in your states rules of the road book it will state the distance a light must be able to be seen at, usually 500 feet, it depends on local ordinance though. It is customary to give a warning for a dim light, but some places that don't get much traffic write the ticket as revenue.

Yes you can, because it may not be clear if you hit the brakes or not. Just tinting them alone may get you pulled over, but you will most likely get a warning

It appears that you have been so, obviously, you can.

It comes under construction and use regulations and the required brightness of lights.

yes. my dad did.