I'd say Longs first, followed by duals and then a high pinion diff. I had my rear differential rotated and it works great with about 4 inches of lift and 35 inch tires.
Having the high pinion won't necessarily give you the correct angle, just less of an angle when it's aligned properly which will reduce the bearing wear slightly. It only take a few degrees to get a vibration in a DD.
With the 4.70 gears you have a very capable rig and I'd make sure it's bullet proof before adding more toys. I do love my duals with 4.70s in the rear, but it's more for the stock low range than the really low gears. I've found in Moab that low-low 3rd is just about right and oddly enough is just about the same as 4.70 1st.
The reality is that the single 4.70 in 1st gear is just about a pefect gear. It is slow enough to truly crawl, but still has just a bit of momentum to keep you going.
