I have heard people mention rear locking hubs and not locking diffs for for what I have. it is probably best if I just get a 4x4 and then I wont have to worry about certain limitations.
You will be fine with a 2wd rig... it’s your terminology that is getting you confused. You can add locking hubs to the rear hubs, but in a 2wd it’s not going to do anything for you unless you are flat towing. On the rear axle of any unmodified rwd vehicle the hubs are built solid to the axle shafts. I didn’t know Warn even made a rear axle free spin kit for the Nissan Pathfinder. I’m going to have to look into this now.
You are wanting a selectable locker (if one can be found for a Nissan Pathfinder) like an ARB, Eaton E-locker, or an Ox Locker. These all install inside the rear differential not on the external part of the axle shafts.
Lets start over with your projected build.
what are your overall goals for Overlanding? What kind of terrain are you going to be covering? What is the most difficult trail you plan on exploring?
Look at Prerunner Nissan Pathfinders, they were very popular back in the 90’s and very capable. Look at how they were built mechanically and set yours up similarly. Keep in mind Prerunners were essentially desert race trucks so were built to go fast and be light where your rig is going to be built to haul gear and move slowly over the trails.
My Bronco has only seen 4wd once, and that was just to see if it worked. I have gone a crossed some narly trails and over some challenging terrain since getting my Bronco last year. My previous rig, a 2000 Dodge Ram 2500 with a magnum V-8 I owned for 7 years and had to use 4wd 3 times, once due to driver error parking on top of a stump and getting hung up, and 2 times to get traction in the snow while pulling other people out on the trail.