We recently let some BYOD devices enroll in JAMF but they are not company owned devices. The employees now want to get them unenrolled after learning what the MDM client abilities are. I know there is a command to remove the framework and unmage the macOS device. Though is there an easy way to remove any applications that were installed via enrollment script or self service ?
Not easily. It depends on what apps have been deployed and the methods used (i.e. pkg installs, Mac App Store).
Adobe CC (for example) provide an uninstall package when you create a deployment package using creative cloud packager, but that is one specific case. Others might just need the .app bundle removing or a vendor script run.
Are there a lot of apps that have been deployed to the devices?
I'd start by doing some searches for uninstall scripts for the various products you need to uninstall. Either vendor supplied ones, which do exist in some cases, or ones built by the Mac admin community. For example, @talkingmoose has had an uninstall script on his blog for a while to fully remove Office 2011. But that's an old app at this point. You mentioned Office 2016, and I'm sure it can be modified to work with version.
Since macOS doesn't really have a universal uninstall function like Windows, you will likely need to run various scripts to get the apps off the machines, at least in the case of items installed with regular package installers.