Has any worked with both of these agents on the same device(s)?
Execs want all the devices (inventory) in a single pane of glass. So Workspace one is getting a POC. Right now we aren't managing iOS devices with JAMF. Can I DEP and VPP with two different management solutions?
Depends on what your Execs definition of Single Pane of Glass is.
Jamf and WS1 cannot live on the same device (MDM won't allow it), but you can use Apple Business Manager to point Macs to one MDM vendor, and iOS to another. Just not a device to both.
If inventory is your "single pane of glass" Jamf has many ways to export inventory data to other tools like SCCM, Intune, ServiceNow and others while directly managing anything with an Apple logo on it.
Single Pane of Glass should not automatically mean all devices need to use the same management tool. When we use Jamf and feed the info else where, your devices can be managed with the right tools for the job and feed into whatever centralized source of truth for inventory you choose.