there are books written... multi-volume... addressing these very questions....

Tractor: clean air in, accelerated air causing thrust loss as it sweeps over the fuselage and tails....

Pusher: No fuselage to funk up the accelerated air... but a lot of crudded up air going into the prop from fuselage and tails... actually can be an irritating source of noise and potential prop fatigue...
there is a theory that pushers have added pitch stability if the prop is at the back of the plane....

Trying to run the thrust line through the CG is a myth..... you want to align the thrust line with the center of DRAG. (As much as is practicable)
this can be attenuated if you have a simple gyro on pitch, or even a throttle-elevator mix....