After additional testing that included multiple reboots, double-sided printing to a duplex printer now works when printing from the guest via the host HP Universal PCL6 driver or the PS driver. Color now also works, but just when printing from the guest via the host PCL6 driver. Color content sent to the PS driver still is not working and has not worked since the VMware Virtual Printing was split out from the VMware Tools installation.
Recap issue: Color content printed from guest via Virtual Printer to host HP Universal PostScript driver always prints B&W on color printer. Same content printed from host to the same printer always correctly prints in color. (Possibly related issue: Host printers do not appear in the guest Devices and Printers list, although they do appear in the drop down list for printer selection).
Historical context: Virtual printing from the guest to the same host queues/drivers and printer all worked correctly until VMware Workstation Pro 15 that decoupled installation of Virtual Printer driver.
Windows 7 Pro 64-bit host and guest (both fully updated)
VMware Workstation Pro v15.5.1 with reinstalled/latest VMware Tools (v22.214.171.12449434) and reinstalled/latest Virtual Printer (v1.1.1)
HP Universal PCL6 driver (upd-pcl6-x64-126.96.36.19995) and HP Universal PS driver (upd-ps-x64-6.5.22695) with separate queue for each driver
HP Laserjet CP2025dn printer (duplex capable and network connected)
Current conclusion: Given that printing from the host to these PCL6 and PS queues works correctly, I consider the color failing with PS queue to be isolated to how the VMware Virtual Printer passes the color content to the host printer queue.
Next step: Pending feedback via this forum...
First, update HP Universal Printer drivers to latest versions
Then open ticket with VMware Technical Support for further trouble-shooting of the Virtual Printing components