You can install the FCS client on workgroup computers, of course this poses a lot of issues and challenges that you have to handle, the important things to cover is:
- Updates, you will have to use internet updates not WSUS, or you will have to import WSUS configuration in the local policy.
- You will install the FCS client using the /nomom switch, which will remove the MOM issue, but you cannot manage and report them from MOM. Disabling the Mutual authentication will not fix the issue.
- Policies, you will have to do that using registry key to apply the required settings.
Check the FCS documentation for list of settings has to be maintained and how it is done using registry.