I wonder what are you actually trying to do... Do you have your tree set up the way you have it because you really want to have it this way or just because it looks to you similar to what you are maybe used to in Catia?
First in FreeCAD you should probably use the sweep for this (if you absolutely want to work with FreeCAD part design and body, if not, there is also Part sweep and Curves PipeShell), it allows you to pick a path and set one or more sections for it, this would then already check off at least one of your wishes
Second, here is how this tree that you have here in FreeCAD would actually look like in Catia:
- you would have an assembly and four parts in it
- in the body of part one you would have what you have in "Body"
- in the body of part two you would have what you have in "Body001"
- in a geometrical set (or a hybrid body) of part three you would have those objects that you have between Body001 and Body002, Link_to_DatumPointXXX would be "past special result with link" of points from part one and part two
- and in part four you would have again some "past special result with link" of objects from part three and the multi-section solid from it
(PS: I don't know if this would actually all work in Catia, but I promise you, from a correct analogy of objects and tree structure this is how this would look in Catia)
Is this what you actually want to have?! Or would you do this in Catia all in one part with multiple bodies and/or geometrical sets? As I said many times before FreeCAD bodies are implemented wrongly, don't get confused by the name, if you write chicken on a cow it is still not a chicken, FreeCAD Bodies are actually "special" limited parts, same as if you would have in Catia a special type of a part where you would be able to have inside of it only one body and be able to use in it only the tools from Catia part design. And this is wrong, and this is why they should be fixed. Proper bodies don't have their own origin, all the objects inside the body still references back to the origin of its part.
If what you want is actually to have like a single part, then my best suggestion, at least for now is to move everything out of the bodies and try to use other workbenches instead of the part design (if you want just solids with ordered features set then part design is fine), in this topic you will find a link to a model that shows some of the possibilities that IMO work quite ok https://forum.freecadweb.org/viewtopic.php?f=8&t=38388
We could talk a bit more about some of your wishes but in general they are good, however I don't see much sense in improving this (and similar things) before some much more fundamental things get fixed and improved in FreeCAD first. I still stand by the suggestions I made here https://forum.freecadweb.org/viewtopic. ... 10#p320885