The old coat of solid stain that has weathered makes a good prime coat if it's clean, dull & dry and is a sound coat, meaning not peeling or compromised in some other way. Duration is a house paint, whereas the other is a stain. The chief difference is the dry film thickness and sheen. the thin dry film makes the stain follow the contours of the wood and can give you a more authentic or maybe even rustic look, depending on the wood. It will almost always be flat, with no shine at all. The thicker coat will more fill in the grain of the wood and probably have an eggshell or higher shine, maybe even to a satin or semi-gloss. It most likely will not be available flat. A thinner coat means shorter life, the trade-off reflected in the price. A properly applied thicker coat of duration can be expected to last a good long while, but I wouldn't use anyone's "lifetime". If the wood has roughness or character to it, that you want to exploit for a certain look, I'd put stain on it. If the wood is smooth, almost shiny the way it is, I'd use house paint.

I'd do SW's Alabaster on the trim to replace the teal color. Very pretty house!

You will need to remove the shutters for painting anyway so why not see how you like it without them. I would not paint the brick IMO it always lessens the value of a home.I like sage greens or grayed greens with brick and I think you could go quite a dark shade of that on the shingles.Then maybe beef up the trim insted of the shutters

I hope you meant to say restain the siding and not paint. Paint will peel. If you have no peeling and the color has simply faded, then you are looking for a new stain color. Duckback produces a very good stain.