No materila is going to be mildew proof that comes from the climate and anything will have to have it washed off from time to time. The composites get it just the same just a bit easier to remove than from wood.

hmmm i agree on the idea of using what you have with those diagonal posts. one thing i think we all need to see is how the house would look like without the landscape covering up the front as it is hard to tell when we only have the 1 photo , if you do decide to remove the landscape it would give us all a better picture of how the facade would look and what may compliment it.

Why replace the hydrangea? You can cut them back in late fall to almost ground. Other bushes should be pruned this fall. Your garage doors would look better with the top panel in windows. I much prefer a single door with sidelights. This one style to consider. A black door with white sidelights would look good. Think you could even do a unit that leans craftsman.

Follow Dark Sky guidelines for your outdoor lighting. Light the paths with downward-facing path lights. Place dark sky wall or ceiling lights near the door and steps. Forget flood lights and "outdoor sconces on the right and left of the front window" that would serve no purpose. Turn on lights only when needed. Don't install lighting that illuminates your neighbors' properties. Dark Sky Friendly Home lighting Program