Mine all sit on Lima Western chassis except a couple I picked up already started with custom built bogies. Thing to do is cut the top of the motor bogies flush and fit it with a press stud having ground out the roof as thin as possible. Should give near correct ride height, although the wheels are solid and should be spoked. Always just tack the stud into place first so that you can be sure the body sits level, needs a certain amount of trial and error as the motor bogie is offset. Get enough weight into the body as you can, low down as well. I have two pairs of locos with one power bogie between them, well weighted they'll handle around 20 old type Hornby HAAs quite easily. The instructions if I recall correctly suggest cutting the Western chassis up to fit. Tried with the first one and decided the press stud method was far easier.
Pantographs on mine are Lima, not strictly correct but readily available at the time and better in my opinion than Somerfeldt. Pretty sure that Judith Edge now does a kit for them.
If I can help any further please ask.
Edit, just looked again at your first photo, buffers should be round and the beams attached to the bogie. I wonder if these are a later version?
Further edit: Looking again they are, I'm almost certain EM2 or class 77 bodies, the side frames are 3 axle types (Co-Co), the 76s were Bo+Bo. EM2s that I have are all modified Tri-Ang