I would say keep the door light. A hunter green door would really weigh that area down.
Zipper:
We have a pale reddish/orange brick on our home as well.
The upper part of the house is cedar siding, and the roof is pale brown-ish (some orange).
We painted the entire house “Burlap” (Bear paint, fromHome Depot). We also painted the front door the same color, and got a nice screen/glass door in a slightly lighter shade. I think it will contracts nicely with your white trim.
My in-laws got a grey siding that looks very nice, too. White brick, though.
-Cem