Mitsubishi Pajero and Tritons have 28 spline front shafts. You can source end caps from Bilal Gunj for Rs.1500, because i got them for my Gen 2.
But you said the splines on the B-Series are 26 in count so the Mistsuibishi ones won't go on.
I've been looking at the front diff setup for the B Series and its not different from the Pajero Gen 2.
So the switch you say is there for activating 4wd is actually activating vacuum solenoids to engage axles to the differential
If you put end caps on and the 4wd switch is off. The wheels and axle shafts will spin freely. When you switch the 4wd on, then the front propeller will apply power to the diff and the diff to the axles and the wheels.
With the end caps the axle shafts will stay locked to the wheels but the entire wheel and axle will spin freely of the diff. Only when you engage the 4wd switch the diff will lock itself to the front prop shaft and apply power to the axles.
Auto/Manual hubs are used because they give you an option to disconnect the shaft from the wheel so it stops the axle from spinning thus the belief is it prolongs axle life.