maybe you could work with the green and not the yellow? Benjamin Moore Yellow Finch

Nice home. You really have a lot if options based on the colors in your bricks. What colors do you like? Which don't you like? Since the shutters arent changing & appear to be close to BM Salamander, what about BM Winter Lake or Squirrel Tale? Try finding a color in their online gallery close to the shutters & check the suggested coordinated colors. Best of luck.

Had to look up justina blakeney, and found this pic supposedly from her book, perhaps a blue like this would contrast nicely with the dark grey, go well with the bright colored interior, and still be toned down enough from bright red or orange....

I am doing the same as DLM. Mahogany door stained on outside and inside. My interior will have white trim. Wood floors and some stained wood stair parts, and other wood accents to pull it together. Or you can paint your interior door.