2. Haldex can send power to the rear axle w/o the front wheels spinning. The controller receives information from steering wheel angle, accelerator depression rate to determine whether the likelyhood of potential front wheel traction loss and pre-engages the clutch before there is actual slippage. That is why the preferred way of driving the haldex AWD unit is not to get off the brake and slam the accelerator right away, since doing that does not give the haldex unit enough time anticipate the potential wheel slip situation. Getting on the throttle moderately and then going full throttle a short while later will usually result in power laid out in all wheels.
3. From the dyno graph, One can assume the max clutch pressure determines the how much power goes to the rear axle, with its peak power transfer of 170 power units, which is indicates some slippage given the front axle still delivers more power. This will also be different depending on the gear the dyno run was on since the torque output from the transmission would be different in each gear.