The desktop packages for Gnome and the ones for XFCE will be shared between the Zorin OS Desktop and Zorin Os Lite Desktop respectively.
The short answer is "yes" you have multiple D.E.'s. But you do not have duplicates of all the D.E. files.
I think that last option:
Navigate to `/usr/share/xsessions`
Right click and remove any unwanted entries.
is the best one...