It's also an asinine non argument that 3 sets of 5 on a few barbell exercises is going to build up the endurance and work capacity needed for rucking. Equally asinine is the notion that such work capacity can be built up in a couple of weeks of endurance training or maintained by doing endurance training once in a blue moon. What needs to be discussed is not weather barbell training can improve rucking performance (of course it can) or whether significant endurance work will still be needed (of course it will) but what is the best way to utilize both for optimum results.
Skewer away. I believe pullups and farmer's walks would result in more carryover to a wide array of functional movements. The pullup more than the chinup because it works more back than bi's, the muscles used to climb up a net or over a wall. The chinup works more bi's. From what I've read, people in the tactical community already train pullups rather than chinups for this reason. The loaded carry works the body through the whole gait pattern, while squats and deadlifts do not. When I used squats and deadlifts to prepare for hikes, I found that I still got sore in the hips - from the loading of that rolling transition from one limb to the other.