Keep in mind that Notion 6 does not change, all that changes is the activation. So uninstalling then reinstalling from a download is not necessary, just re-activate Notion 6 with the Sphere license and you'll be good to go.
You can leave Studio One 4 installed, Studio One 5 get's installed right next to it and uses the same assets from the documents folder that you had in v4. With Studio One 4, any files you open from v4 in v5 then save, you won't be able to go back to v4 and re-open them.
As for deleting files and applications on a Mac is the same as you would with anything on a Mac
- To uninstall any application on a Mac just drag the application from the Applications folder to the trashcan.
- User data is stored in the Documents folder, same thing applies, just drag anything you don't want to the trashcan.
For PC Users:
- In the Search Entry in the Task Bar type: Uninstall
- Select where it says "Add or Remove Programs"
- Select the Application you want to uninstall.
- User data is stored in the Documents folder under respective directories for Notion and Studio One, inside those folders are the song files, soundsets, macros, etc, to delete what you don't want just right click the folder(s) or file(s) and select where it says "Delete"