RE: CAD motors, servos etc
I doubt any of us will look at CAD renderings of that sort again without giving a thought to the hours that go into such a project.
As for the CAD servos and such I can't offer anything other than to use what you have or buy what you think you'll need so that you can model them correctly. Some of this stuff is out there but as the products we use are constantly superceded by new ones the CAD files become outdated other than to those of us with stocks of the old servos and motors that we still have and still use. If you find what you want then great, but in the end buying the servos and motor ahead of doing the design work is not a bad option if you are going to use them in the eventual build.