The Zorin OS Desktop Lite is not yet configured for Zorin OS 16.
The Release of Core is first. Zorin OS Lite, Ultimate and Education (core and lite) follow.
When the ZorinGroup announces the release of Zorin OS Lite (Either as Beta or as final release), users will be able to access installing the Zorin Lite desktop from the Zorin Package Repository. This can be handy for a Zorin OS Core user that would like to experience Zorin OS Lite without doing a full reinstall.
To do so on Zorin 16 (Beta or Core final release) prior to the release of Zorin 16 Lite:
sudo apt install xfce4
Follow the prompts, including configuring LightDM
This part is if you have numbers in your login password:
sudo apt install numlockx
sudo nano /etc/lightdm/lightdm.conf.d/lightdm.conf
Add this line: greeter-setup-script=/usr/bin/numlockx on and save and exit.
Install the Zorin Menu for Zorin Lite Desktop:
sudo apt install xfce4-zorinmenulite-plugin
While this is not the fullest Zorin Lite experience - it is reasonably close. The user will need to configure some things and may not have the dockbarx without installing and configuring that as well. The desktop itself is the same as well as the performance.
EDIT: (A long time later)
For those who want XFCE 4.16 (instead of XFCE 4.14) on Zorin 16:
If you have already installed sudo apt install xfce4 or sudo apt install xubuntu-desktop then you can add the repository:
sudo add-apt-repository ppa:xubuntu-dev/staging
sudo apt update
sudo apt upgrade
If you want to install fresh, then add the repository as above, then sudo apt update followed with sudo apt install xfce4 or sudo apt install xubuntu-desktop
Be aware that XFCE 4.16 is the version that is partially switched over to CSD's.