I'm afraid of losing existing edits to many files, as well as projects I am currently in the middle of. Will all catalogues, as well as individual collections, group sets, virtual copies, and file edits over the last 2+ years be seamlessly transferred over if I switch from a desktop based LR4 to the Creative Cloud?
Yes. You simply upgrade the catalog during installation.
Your original files remain untouched and the catalog settings are automatically re-linked.
Thanks for the reply and the peace-of-mind!! Cheers