I'm no expert on on-road car tips, but I did a bit of an on-road re-engineering project way back when, myself, converting a Kyosho Turbo Optima to an on-road car, my CYANide project. It turned out to be a much bigger challenge than I expected. Narrowing the track width of an offroad car, and keeping it 4WD was probably the biggest amount of work. Different arms and custom hybrid CVDs had to be sourced & made, something I see you've also done. For shocks, I needed to make them a lot stiffer than what would be typical for an offroad car, so heavier weight oil was necessary, and stiffer springs so that the shocks would uncompress properly. Your idea for the sway bars looks excellent. I don't think it matters if the sway bar is mounted ahead or behind the control arms, if adjusted right, they'll work properly either way. I had to re-think mine, tweaking the adjustment of the stock rear sway bar and removing the front one completely...with the narrower front arms, it just wasn't possible to include the stock sway bar.
At least you started with a DS, which is already an on-road chassis to begin with.
