Something I’ve found useful is using workflow properties to allow a jira-admin rights to edit closed issues. I started putting these workflow properties in so that any jira-admin, could edit a closed issue without having to reopen the ticket and mess up the issue’s change history. More on that in this link:
You should have two properties set for this to work. The first makes the issue editable. The second specifies what group can edit at that specific workflow step.
1. Property Key = jira.issue.editable
Property value = true
2. Property Key = jira.permission.edit.group
Property Value = type-your-group-name