I know a lot more about 4000's, but here's what I do know.
They are broken down by installation. Airbus (either 300 or 310) have D1, E1, H1. 767 has D, E, E4
. 747 has G2.
Contrary to 4000's the 767's and the G2's definately have internal differences. The archetecture is the same, but I believe some of the G2 design and materials are better. Meaning the turbine discs and mating hardware.
As to the difference between 767 and Airbus, I believe that it is mostly installation related, meaning anything that interacts with the airframe. Cabin bleeds, tube placement, and especially the gearbox. Airbus have two hydraulic pump shafts, and Boeing have 1. I think the internal parts are identical, at least comparing A and B models of like thrust levels.
I don't think you can convert one to the other, even Airbus to 767. You could physically do it....but it would not be legal regulation wise. 4000's can be swapped model to model, A to B to McD under the instructions of Service Bulletins. Can't recall being able to do that with a 7R4.