Unlike 7 mode (for FCP only as well) the data for the incorrect path is not going on the IC/PB. it goes via the cluster network, by default on the AFF200 it's ports e0A and e0B which are 10GB each (can also use other ports - on the same speed).
it should add very small latency (around 1ms).
as NFS v3 is stateless. i would place the LIF on the same location as the volumes. and let the LIF failover to handle redundancy. in NFS v4 or if pNFS involved - need to read some docs, but in general from my experience the LIFS fails-over faster than the aggregates... (assuming ARP cache on the switches not creating any problems).