1) Each interface has a unique layer 2 address. If they are ethernet ports then they will have a unique MAC address per port.
2) The wildcard mask is just a stupid way to express a 'normal' subnet mask. It is a completely pointless way to express an already confusing subject and Cisco should be punished for their inconsistent use of mask type.
In your case, OSPF will advertise the network 192.168.12.64/26 to his friends in Area 0. This means OSPF will tell them that he has a path to any host with an address between 192.168.12.65 - 192.168.12.126. I prefer to just turn on OSPF on the interface itself, that way it automatically grabs the subnet without you need to type it in.