When you run through the initial setup i it asks about the admin host and the filer IP.
Admin host is useful if you want restrict management capabilities (of NetApp) to a particular machine only (say IP address of your mgmgt server). If you leave it blank, there are no restrictions.
Filer IP address is required to access it over network, rather than only via console cable.
I would assume that it would be better to configure e0a and e0b as a on both PCMs as a VIF
If you mean vif spanning two controllers, this is not possible - each controller has its own identity & network config, with the exception when failover occurs & failed partner is run as a virtual instance on the surviving controller.