Question one: I would not paint the garage door the siding color. It would keep it the same color.
Question two: IDK. Color needs to complement and also must be done in the right percentages. I have seen homes like yours in Aberdeen, NJ with the same brick color and used white as the window trim and it worked
Question three: What ever color you use on the sidelites should also be the posts.
Question Four: A retractable screen will look fine as long as it is installed cleanly.
Question five storm door trim should match the sidelites.

THere are internet websites you can use to choose colors. You choose the style of home and add colors to the trim, garage and siding to see if the colors work.
The issue is what looks good on the computer is not the same on the home. Every single paint color is made with different percentages of color thus when you paint different colors emerge depending on what color is nearby.
Hawthorne yellow is a green yellow on my exterior home whereas in an interior room it has a butter yellow.
I painted a home recently a cream wheat color but it is a light yellow on the clapboards.

FInd an artist. Find an art student and ask them their opinion. They tend to understand color and percentage of color on any project.