In version 11, it is possible to configure a field to be mandatory, optional, hidden, or read only per status per user role. In version 12, it is not possible to make this property change per Status. It could still be different per user role for editable, hidden, or read only, but not for optional vs. mandatory.
Workaround: Use field dependencies based on the status field to show or hide the fields that are necessary or not for each status choice. Use the rule action to show or hide a field. There is no workaround to make it specific to a particular user role or change the optional vs mandatory property.