If the exhaust flow is restricted, yes. What do you mean by "bad"? There are different types of failure.
With those cam sensor faults and the cam/crank correlation fault the computer can go into limp-in an set the rev limiter to 2500 RPMs. P0016 suggests the timing belt is off but if the cam sensor is failing this fault may be invalid. Was the timing belt replaced recently?
The blinking brake light is because of a low brake fluid level in the reservoir, refill and inspect the brakes.
The fuel filter in not a maintenance item on the car (like most cars), it doesn't need to be replaced on schedule. There is no mass air flow sensor on a Neon.