You usually get a bend in the track rod if the tracking has not been done for a while and you need to heat it up because it has seized. Where it twist's that's when you get a bend

Not unless it's had a whack
This should'nt cause vibration but will deffinately through your tracking out when driving as it will not give an accurate line for the wheel's to follow.
Also, did you change the bushes on the rear of the lower arm's? If they're not up to much cop then what will happen is when you accellerate your wheel's will through them selve's out, causing the wheel's to toe out.
Not sure if i'm right in thinking but has the car been sitting for while? As this will have caused the tyre's to have flat spot's.
Were the top mount's re-newed? This also could cause the steering to be tight if the bearing's are a bit stiff.