Um, no, the G-wagen is not an LR derivative.
Um, yes it was. Same frame, doors, the works.
I used to work on both. The only difference for a long while in the mil spec models was Mercedes had an excellent 5 cylinder diesel while the 90 had the 4 that was in Taxis.
The 4 was indestructible and could run on anything but had something like 65 hp and was just painful in a heavy vehicle.
Now is there a material difference between the mil spec defender and the G wagon? Yes, they’ve drifted far apart..