Best way to do a non disruptive migration to a new Flexpod

[VELSOLADMIN]

I have a new flexpod that we are going to be installing. The new flexpod has Nexus 3548 switches. I need to connect a the Nexus 3548 switch on the new flexpod to our existing 5548 on the old flexpod. I don't have a maintenance window to migrate the virtual machines so I would like to storage vmotion them first and then move the vmoiton the compute after. I want to connect two ports from each Nexus and setup a 20G LAG. Right now we have our storage vlan for NFS and the networking vlan for VMware on different subnets that don't touch each other. Once the vms are migrated and running on the new flexpod they will still need to get out to the internet via the old 5548's until we migrate the top level networking. How would I do this with my 20G LAG? The UCS Fabric interconnects and the NetApp are on their own port channels using vpc between both 5548's. I would like to setup the same thing on the new flexpod with the 3548's. The old Flexpod contains the following:
vSPhere 5.1 (All datastores are NFS)
UCS B230 M2's
NetApp 3240's DOT 7 Mode
Nexus 5548's

The New Flexpod contaisn the following:
vSphere 5.5 (all datastores are iscsi VMFS5)
UCS B200 M3's
NetApp E5500 running Santricity
Nexus 3548's

Whats your opinion on the best way to configure the Nexus switches to accomplish this non-disruptive migration? Thanks.

[mharding]

Hello - thanks for sharing the detailed solution components.  It doesn't seem like a validated design, so I can't point you to a specific Deployment doc.  I'd suggest getting information specific to the Nexus if that is your biggest concern.   You can ask the FlexPod reseller you're with with, or your Cisco account rep.  

Other useful sources of info to assure FlexPod continuous operations include this technical report and these videos we created on the topic.  They do include content on networking:  https://www.youtube.com/playlist?list=PLiqnVV70RJjYRWniMtH5tgRg09jMa_Cld