Hi ,
It should not be necessary to have the Launcher installed in order to run the Editor that you have built from source code. The first time you run the Editor, it may begin to install the Launcher, but you can stop that process and the Editor should continue to run fine. I cannot confirm that however, since all of our computers here have the Launcher installed. I should probably look into the possibility of having at least one computer set up to use only versions of the Engine that were built from source code.
It is also theoretically possible to copy the Unreal Engine folder after the Engine has been built and place that copy on another computer. This is also something I have not actually tried outside of using source control, so I cannot confirm that. It might be worthwhile to investigate setting up a source control repository for both the Engine and your game project.