Душ на открытом воздухе

An outdoor shower(8 x 12 feet) at the back of our house. We want to incorporate some design elements from our home that was created with the help of arcbazar 8 years ago. This will be used for showering off outside after long days of outdoor yard work and washing our 2 dogs, Cooper and Marley.

We live in a secluded area so no close neighbours but need privacy on the sides so no direct line of sight into the shower from the driveway and front entrance.
I would like to incorporate timberframe to match our screened in porch, corrugated steel, cedar siding, natural stone (maybe as a feature), open to the sky with a lattice roof for vines possibly and to let natural light in. This will be placed alongside existing landscaping and we would like to integrate them together. We have lots of hostas and ferns that could seamlessly transition from the outside landscape into the shower area.

Clean lines, simple design, not too “busy”.
Rain head, hand wand, exposed copper plumbing (will drain system before winter)
Practical to build.
Not massive in terms of weight. The right side wall will sit directly above a buried concrete septic tank. I was thinking of using trapezoidal concrete piles sitting on the ground to support the timber frame beams. See photo of garage man-door for similar piles.
Hide 2 round green septic tank lids shown in photo. I am positioning the right wall of the shower adjacent to these lids and thought they could be covered with a removable wooden plank rectangular lid that we could place some flowerpots on. The wooden lid would have to be lifted off when the septic tank needs pumping annually.
Withstand outdoor winter conditions
No permanent foundation
Complement the existing architecture
I am not sure about having a door but my wife wants privacy so open to ideas of how to design so no direct line of sight into the shower.
For floor we are thinking a cedar platform below the rain head and river rock and flagstone for path to platform. We will bring hot and cold-water lines outside from the mechanical room behind the stone wall shown in the photos. I have some stone left over from the house to use in the design as an accent of some type (optional). Remember weight is a concern so accent only.
The back wall of the shower will be in front of the heat pump shown in the photo. I would like to hide that heat pump from view from the front entrance.