The issue isn't related to Xerox, either update the Macs to 10.12, or call Xerox and see if they will do another escalation on your behalf to MS and Apple for OSX 10.11.
We have an environment with MAC users, most of whom are on El Captian 10.11. We tested this solution on a laptop with Sierra 10.12 and it seemed to fix the crashing for Office programs when printing. However it didn't work for the users on El Capitan 10.11. After the troubleshooting steps users were able to print once, but the program would crash after trying to print a second time.
Thank you for supplying this information.