SQL Server : what licence is required?
You should call a Microsoft licensing expert and talk to them. They would be best person to resolve all your queries. Microsoft licensing is bit comlex and varies per environment.


  I have 2 servers and I'm looking to have the first as a Primary and the second as a mirror (as a reporting server and DR server), from what I can see on Microsoft's comparisons I should be able to do standard but am I missing anything?


You can use standard edition in SQL server database mirroring but you cannot use Snapshot functionality to get report as Mirror server is always restoring and you need to create database snapshot on mirror to run reports but snapshot is enterprise only feature. If you use transaction log shipping with Secondary database in standby mode you can run reports although when log backups will be restored users will be disconnected.


  I understand I would need to manually promote the mirror in the case of DR, but would enterprise make it easier/faster?


Whether you need to manually promote mirror to principal or it does automatically depends on your mirroring configuration. If you have witness with automatic failover it will take care of automatic failover in most cases IF it is able to form QUORUM. Also database comes online after second phase of recovery in Enterprise edition but after 3rd phase in Standard edition. There are 3 phases of recovery analysis redo and undo.

PS: Please tell me if any further clarification required