The Vulkan 3D will be added at the release date of the Application Game Kit Studio which will take some delay during more Vulkan test The Game Creators needs to perform.
About 3D scene editing there are no information yet, because the programmers work on fixing things and bring the program to release bug free state.
After the release, sure there will be some nice surprises to see. But I prefer a complete programming language and add some other more important features like, GUI and Native window forms libraries and this asset protection thing with File Blocks and other more programming related stuff, instead of a 3D scene editor yet which is not vary mandatory for now.
Maybe this 3D Scene editor we will see it as a DLC in the future. If you have subscribed to monthly newsletter you will see there is one DLC with 3D Particles editor (Sure is not a scene editor) but is a starting point of the 3D Scene editing.
I believe the 3D Scene editor will be as a future DLC but it will not be ready soon. But I prefer the developers to focus in the more important stuff I described, instead to work in any 3D Scene editor yet.