Scully, Julie..(& unless you've put on 80lbs) then still
looking like Dana Scully!
If we use the pic as a model then my initial thought is obviously everything in 2 x's...
pillar support & stabilizer, so i'd initially look at making a connecting plate to be screwed into the soil (this is tall therefore needs anchor plates)
As neither is straight weight support is essential (regardless of how light or otherwise, the leaning angle of the top needs taking into consideration within the ground anchor.
I'd use a solid metal bar ground stake within the blue pipe (pipe slipped over it after siting) that takes all weight up to the height of the rear wall, so you'd simply have a straight stake to that point & made it flex from above that point, all below would be bave to be built higgledy piggledy, mere perspective, vs construction required. (see below)
The unsupported upper section would have matural bend from the point of the end of the internal bar stake, this would be accentuated by the build to give the "teeter" effect
(ok bear with me) flight case clips or similar so they can be pulled tight to the body of the upright, but also undone & removed with 2 people instantaneously.
So connector plate, small "connecting box section" containing thickish blue polyprop water pipe lengths allowing a degree of flex & stabilisation as you build up in segments & place them over the blue water pipe.
in other words your blue pipe is "planted" & you make up wall pieces with a central hole & slot them over the pipe which is eventually hidden.
This also provides a good solid screw in point for hinge supports on your pvc gate(s).
For the curve of the wall use a pre bought section of cnc'ed board that has lots of ridges cut into it to allow curvature you see in modern shaped shower cubicles etc, i'm looking for the term but it's "stuck"
..you know those kids snake toys made out of wood but with hundreds of little cut-outs that allow almost limitless flex akin to a real snakes movement, ..well that's the sort of thing this board allows.
Of course you would be left with alot of stone frontage making, but hey, it's a stone piece after all.
Anchor plates temporarily screwed into the ground are the key though!
Without getting too far ahead of things, pipework along the length of the lower parts of the wall to feed seeping fog to the gate frontage down one side
No, i'm not back.