A green roof pairs well with gray and white homes. For a subtler look, pair a green roof with a siding in a lighter shade of green. I think you are on the right track .You have chosen harmonious shades . New paint doesn't have to match existing colors, but it should harmonize. Some general tips are- Green roof - Gray, green, or white house colors. You could use a dash of yellow also.

If you use masonry paint, we could head in a warm greige direction for all of it - not so yellow . .. something that can give you a bit more contrast against the white windows and trim - even 40 does a lot for us . . . what about a blue green gray? You will get a coastal / mod vibe and it will relate to the farmhouse look .. .above bm silver mink http://www.benjaminmoore.com/en-us/paint-color/silvermink and below . . . gilbraltar cliffs . . http://www.benjaminmoore.com/en-us/paint-color/gibraltarcliffs Shingle look siding on the side dormers would be neat to get that cottage mod. . . you can stick with yellow but I don't think it complements the roof tone. With the blue-green grays, the white windows and trim will really pop beautifully. . . You can also go more neutral with a warm gray - greige . . . here's the siding tone http://www.benjaminmoore.com/en-us/paint-color/capemaycobblestone paired with this for brick - http://www.benjaminmoore.com/en-us/paint-color/graystone potential future red windows . . .aluminum pits over time, so if you have just one side you want to try, you don't have to powder coat, you can take a small brush and just do them by hand with latex paint if they are 10 yrs old or more. . . one advantage to gray . . future see [houzz=]

I love the roof and the windows. Your house has a wonderful tropical feel to it........ Colorful stucco is fun to do. I will attach a few photos of colors that I like that would look good on your house.........

To answer your question I would paint the body of the house blue, all trim white, and then the "fringe" which I think ties into your porch decking, I would paint it the gray. It is a good "grounding" color for your home. Sherwin Williams has a cool web tool. Take a pic of your house and load it onto their site. You can "color" away on your house. When I painted my house for the first time, I did not want the garage door to stick out, wanted it to blend into the house. Everyone said it would look weird, needed to be painted the same as the trim. Used the Sherwin Williams site and realized want I visioned looked good. I have neighbors of dubious design skills! Ha! Ha!