could be bad rotors, or brake pads wearing unevenly, which would result in bad rotors.
check your brake linings they have little metal tabs that will rub the rotors when they are bad. could be a wheel bearing
It could be the rotors are getting bad, and it also could be the car's wheel alignment.
No just put them on. If they were bad they could be sued for a defective product. Actually Honda/Acura specify that NEW rotors be "refinished" with an on-car brake lathe...
There will be a pulsating on braking.
There is a pulsating on braking.
Grinding
That depends. you could have warped rotors or bad pads. or maybe you got some gravel dust in them.
Is it accompanied by a shuddering or vibration? You could likely have bad brake rotors.
No just rotate smoothly Could be bad or mis-adjusted wheel bearing Loose caliper or wheel
it could corode things and it is dangerous for kids
It could lead to stress which could lead to other very dangerous things