Hooray for not painting the stone, which adds texture and color to your house. Possible door colors:

dark red:

Or a cobalt blue or black front door with blue or black Adirondack chairs on the porch and lots of potted plants in colorful planters.

Paint the garage door and all trim "greige." I don't think you need shutters at all. Since you'll be removing them in any case, after you paint the front door and put in a front garden, see how the house looks without any shutters.

As for the front garden, you need a lot of shade plants. Go to a small nursery and get their help in designing some front beds of mulch, rock features, low shrubs, ground cover, and shade plants.

If you're going in the cedar direction, consider stripping your current door, staining it a cedar color, and the pillars as well. Or get a new cedar stained door as shown below. Again, do all trim, especially downspouts in a "greige" so everything blends in. Here's an example of trim with stone like yours.

I love that you are keeping the stone. I wasn't sure of a yellow door but I really love the picture posted by @housegal200, the stone's dark accents make the yellow really pop. A dark door would also be lovely. I would add natural stone to the porch to have the entryway pop. Then you could start adding pottery, our French Anduze accents natural stone nicely. If you'd like more design inspiration look at our designer gallery: https://www.eyeofthedaygdc.com/designer-gallery/ 

With the brick you can go with ANY color that makes you happy. I would personally go with either a royal blue or turquoise, but those are my happy colors. If you want chartreuse, it is YOUR house, do what YOU want. It’s only paint, it isn’t forever.