Multi Subnet Availability Group IP Requirement for Windows Failover Cluster
Does the Windows Failover Cluster for a multi-subnet SQL Server
  Availability Group require a static IP entry for each subnet?


The CNO will require an IP address for every subnet it could reside in.


  I am running SQL Server 2012 on Windows Server 2012 Hyper V VMs in 2
  separate subnets in the same domain. I understand that I will need an
  IP from each subnet when I create the listener for my AAG. What I am
  unclear on is the configuration of IPs on the underlying Windows
  Failover Cluster.


For the underlying WSFC you'll need at a minimum:

Node1 - IP Address for each unique subnet for each network interface

Node2 - IP Address for each unique subnet for each network interface

CNO - IP Address for each unique subnet

EX: 2 nodes, 2 subnets, 1 interface per node, subnets 192.168.1.1/24 and 192.168.2.1/24

Node1: 192.168.1.10

Node2: 192.168.2.10

CNO: 192.168.1.20, 192.168.2.20


  Also, if the server hosting the secondary replica does require its own
  IP, does it also require its own unique cluster name (and can you
  explain why this is necessary)?


I'm not sure I understand this part of the question. All of the resources can only belong to a single cluster - there is no cluster inside of a cluster thing.

Edit - I looked at the link that you posted and I'm not sure why the author stated "•Cluster name for each node". My only guess is they meant each node needs a name and IP (for the node). Otherwise it's not a correct statement, the author should probably be contacted.