After installing with AirwatchAgent.msi can I stop the intelligent hub from starting? I want to stage installs without interrupting users.

How are you trying to stage those devices? Just installing hub via the MSI app, or using command line based enrollment command? 

I am using the MSI install with only the server, ownership, OG defined.

/quiet SERVER=dsxxxx.awmdm.com DEVICEOWNERSHIPTYPE=CD LGName="GROUPNAME"

Is this part of imaging a device, or is this being done manually through cmd / a batch script? Ideally I think you'd want to use a staging user to install Hub in an administrator account. Then, once installed, when the user signs in next, they'd be prompted to sign into hub (unless you're using AD and the ASSIGNTOLOGGEDINUSER flag). 

To answer your question directly, beyond the quiet flag, I am not sure we can specifically suppress hub popping up... but depending on the enrollment flow we'd want hub to appear for a user to sign in to assign the device to them in UEM. 

We are staging with imaged devices but for this case we are pushing to the existing fleet. My hope was to have it fully installed and instruct people to open the app and enroll. Not a huge deal, I synced the installer and created a shortcut for them to run with our parameters.

Gotcha. I speculate the reason behind having hub open automatically is to get users to sign in so that it switches devices from the staging user to the actual end user / gives them a gentle reminder to sign in so that any user-based resources also land.