Question

red and blue shift of perihelion and apehilion

Answer 1

It depends on which way you are looking…

If you look behind, things are redshifted.

If you look ahead, things are blueshifted.

HOW MUCH they are shifted depends on where you are in the orbit. The most shifting is seen a perihelion where you are moving the fastest. The least shifting is at aphelion where you are moving the slowest.

Since it depends on direction toward/away from the sun as a specific light source, then it isn’t shifted at either place - as you are not approaching or receding from the sun at those locations.