So far you have five colours for your exterior. I'd stick with one of those for the door and window frames. Hogs Bristle 1/4 is a nice neutral.

Check your local building department as you'll most certainly need a building permit for this modification. Even if it's temporary. Personally I like louvre windows. You'll get good ventilation and the newer products are a world away from the old style ones.

A sliding door is just a big window, and if correctly built in (check if the glass is the correct sized for the door if a bit old) with the correct sized lintels this should not be a big problem as the loads would be transferred to the sides, allowing the door to slide easily. Silicon spray (being a Yachtie were we use this stuff everywhere), we now use silicone spray on all our windows in our 1930 home and the windows glide across with one finger before they used to tilt when trying to open them. I would place the door head up to line up with the others and one thing you might consider is placing a window seat, (rebate the bottom channels into the window seat) and have the window seat in and out, place a cushion over the entire seat, should be fantastic and if the deck is built, than no balustrade is required. If it is a stacker slider, i would do the seat for the entire length. So instead of looking a bit funny they will think it was supposed to be like that. We should all think outside the square more often. RAM

If your block is facing North or West (within Australia) maintenance will be required to ensure movement is minimized. Timber doors are beautiful they just tend to be susceptible to sun damage. FYI Cutek is a great timber protector if you want to keep the natural look however you will need to keep applying year after year.