1) Yes Torsen is real 4WD. The Torsen is only in the center diff to allow power for front and rear axles. The front and rear axles are open. ATRAC handles the traction for wheels on each axle, to allow forward motion with a wheel on each axle of the ground. However VSC is also in play and will limit wheelspin and ultimately throttle back in mud, sand, snow, ice, etc. That is why you can lock the center diff (Torsen), which also disables VSC to allow maximum traction forward. It works pretty well, trust me I have used it many times now. See in the trip report section.
2)Most LS diffs use a clutch pack of some sorts, however the center diff in the transfer case of the 4R is a gear based LS, and therefore doesn't require any additives.