I'm failing to see how you're going to 'reuse' these blocks ( albeit I'm not a 3D user much )?
I need all those blocks in the separate files with parent origin, so I can reassemble them in other configurations of the machine.
WBLOCK is pretty standard for extracting block DEFINITIONS .. you want block REFERENCES within a separate drawing so essentially nested blocks.
Yes, indeed, references of unique blocks in one file. Unique blocks are "nested" within one file. So, one file - one block definition, with (potentially) several references of the same block.
This is where those 4 bolts insert into your example assembly:
Yes indeed, I know location of many components.