I have the first version of the Duff hoops (circa 95 maybe) and they have a little over 5" clearance between the top of the bar and the bottom of the flat section of the wheel well with a 3" body lift. My shock mounts stick up above the bar, but I think would still clear just barely without a body lift. Yours are clearly better positioned both front to back as well as the mounts not sticking above the bar, so I think you will be just fine.
You can definitely take off the front shocks for extra articulation, or just for a softer ride.
The double shocks are definitely a bit of a fad, but also a necessity of the past before better shocks. It is definitely possible to get good performance from two softer shocks equivalent to a single expensive shock, but I think a good single shock is the best choice overall.
If you already have the kit it is certainly worth using, and it is still very functional with the 30/70 shocks, and it is easy to just run a single shock. As you note, the extra shock can mimic the benefits of a swaybar, but only during transition.