This questions is so simple that I can't find the answer to it.
I have 2x v3240s in an HA pair. My simple question is do I need to duplicate igroups and member initiators on both heads or does this automagically happen? That is, if I create an igroup and members thereof on Head A, do I need to repeat the process on the Head B?
No. Those settings will come over when the NetApp performs a CFO. You will need to make sure to have the ipspaces (for multistore) on both NetApps, and all ifgroups/vlans created on both NetApps. This is where most people fail during the setup and CFO's will result in nothing working. When you are done with your setup, run the HA-Config-Checker.exe program that is available on the NOW site.