I have an automated pool with three VMs.
But all VMs are not part of the Active Directory they are on a workgroup.
Can I assign local accounts from the already in the master VM instead of the Active Directory?
This means the pool provisioning is not complete. Chech the status of VMs in pool inventory.
VMs should be in available/ provisionined state so that it can be launched by entitled domain users. Ensure that your DNS settings are correct and entered proper domain information in Custom Spec or Domain Account settings in View Composer configuration
There is no way for local user account to be used for Desktop launch
As SKG said, not only will local users not work Active Directory is a requirement for View: http://www.vmware.com/products/view/faqs.html (one link of many; you aren't the first to ask this question).
Even the third party connection brokers (Leostream for example) require some sort of directory infrastructure (be it ldap, Novell, etc) as you need to be able to entitle users from a shared directory service.