The "Management" port group is used to manage the host itself and it is required only once.
Assuming the DMZ network is also a VLAN on the same switch as the other VLANs, I'd consider a setup like this:
vSwitch0: 2 uplinks (vmnic0, vmnic1)
-> Management Port Group - VLAN A - (vmnic0 active, vmnic1 standby)
-> vMotion Port Group - VLAN B - (vmnic1 active, vmnic0 standby)
vSwitch1: 2 uplinks (vmnic2, vmnic3)
- iSCSI Port Group 1 - VLAN if required - (vmnic2 active, vmnic3 unused)
- iSCSI Port Group 2 - VLAN if required - (vmnic3 active, vmnic2 unused)
vSwitch2: 4 uplinks (vmnic4...7)
-> multiple Virtual Machine Port Groups with different VLAN IDs - all vmnics active
The above is just an example, and you may want to use uplinks from different network cards for each vSwitch and connect them to different physical switches for availability reasons.
André