The only thing I can find is that yes they can be installed to the E: drive during a manual install, with the only issue being that the Full Disk client can ONLY be installed to the same location as the Framework. So you can't have Framework on C and Full Disk on E. As for doing it with group policy, there doesnt seem to be a way within the tools provided but you could use a 3rd party tool to create an MST file and set that with the deployment in the GPO.