Hi there,
This is Bogdan from Romania.
I'm a mechanical engineer - specialized in the industrial robotic field, 3D designer, industrial designer and 3D modeler.
For some of my projects, I'm also doing the physical prototype too.
I'm doing product design, industrial design, reverse engineering, ideation, etc.
I have over 15 years experience working on various systems/devices across multiple industries, from concept to launch.
1 - don't know if you know, but on the scanned files, the middle/reference planes are not preserved and while reverse engineering is necessary to define new planes, cut the piece in half, do the required modeling where possible and than mirror it, with respect to all the parts in the assembly
2 - as you said, geomagic is the best but is not always enough... :(
3 - if you could send me the stl file, i will check the integrity of the mesh and see if is workable - no charge for the checking :)
Regards
Bogdan