Technically it's LACP (802.3ad like you said) and not EtherChannel. EtherChannel is the Cisco proprietary blend. NetApp does not support EtherChannel to my knowledge. Among network engineers when you use the term EtherChannel we hear PAgP not LACP. If a NetApp administrator asked a network engineer to configure EtherChannel you would probably have a broken segment.
To the original poster:
Can I assign a physical port to be used by a virtual nic? Yes
Do I have to have both the top and bottom network cable in a active switch to have a connection on the virtual nic? No
Example. I want to have 1 virtual nic setup on a 75 subnet for manangement and another virutal nic setup on an 80 subnet for connection to servers.
To do this requires dedicated NIC's for each interface (for each subnet really). A virtual NIC is not what you are thinking. You are thinking of a sub-interface that is not physical (or an SVI which is an IP assigned to a VLAN interface on a switch, which NetApp does not do). There is a huge difference here. What the VIF is doing in NetApp is aggregating multiple physical interfaces in to one single larger "virtual" interface. It adds both redundancy and bandwidth. This is why you can have 2 NIC's members of a VIF and only 1 plugged in. VIF is a layer 2 technology. You can still only apply a single layer 3 address to a VIF. VIF is not the aggregation of layer 3 links (per se, although it can do load balancing based on IP so it's layer 3 aware). And when I say load balancing on IP I mean source and destination IP, not the IP assigned to the interface....
There is never a dumb question. We all learned this stuff at some point.