Both DreamLife and DreamConnect store the folders (and their linkage to calendar entries and contacts) in their respective databases. So uninstalling either of them will not delete the folder information.
However, DreamLife stores the folder colours and default alarm sounds in its .ini (initialisation) file. So uninstalling DreamLife will wipe your folder colours and alarm sounds, but not the folders themselves. Since DreamConnect doesn't have any folder colours or sounds, it doesn't have this problem.
(DreamLife also has a lot more preferences, and these are also stored in its .ini file, and so will be lost on uninstallation.)