AD Lock on the trailhawk is, yes. The ADII should be fine as well off road. The Low range adds that needed low end power if you get stuck or are pulling something like a boat out of the water.
ADI should also do just fine off road; it just has some limitations in regards to how hairy the situation can get.
ADI is still going to out perform most other Active/Real Time AWD/4WD systems you would find on cars like the Ford Edge/Escape, GMC Terrain when in an off road situation due to the terrain options available. At least IMO. It's the major reason I picked the Jeep over the competition.
2014 Jeep Cherokee Limited - White Exterior - Black Interior
Luxury Package, Navigation, Panoramic Moon Roof, V6, Active Drive II