They can coexist. At least by what I was suggesting, the whole point is to keep the dedicated superdirt environment in a sandbox, isolated from the rest of the system. If this environment clobbered the main install, it would not be worth doing.
Tidal would launch the superdirt-only version using command line options to control what gets loaded.
The IDE would launch sclang with different command line options and ignore the superdirt-only class library etc.
hjh