Unity <-> Cisco <-> MX7000 (npg) fiber channel, only some WWPNs showing to Cisco

We've got a new pair of MX7000s in a new DC, and I'm trying to get their FC working to the Unity 480 we have in the same room.

The Unitys are connected to a pair of Cisco 9132Ts (not stacked), two cables on each controller connected to each Cisco.  Meanwhile, each MX7000 has two connections from its 100Gb breakout cable connected to each Cisco.  The Cisco is zoned with a pair of zones, one zone for each chassis and all its blades plus all the controllers on the Unity.

Meanwhile the MX9116Ns in the chassis, running OS10, are in npg mode, with each chassis having a vfabric defined and a unique fcoe map for each vfabric, and the vfabric defined on their uplinks and the downlinks to the blades.

Smartfabric isn't an option for us, I don't think... isn't it limited to 256 vlans?  We have more than that.

SOME of the blades from each chassis show up to the Unity... and the broken paths don't seem to have a rhyme or reason to them.  Two controllers, two switches, two ports on each blade... there should be sixteen paths each, but most are at 0, some have 12, some 8, etc.  And every possible path from blade to Unity has SOME initiators visible.

All I can really fixate on is that on the Ciscos, if I run "show flogi database", each fc link on both Ciscos never shows more than four WWPNs plus the MX9116's WWN.  There are eight blades in each chassis... shouldn't I be seeing sixteen WWNs?

It's like there's a limited number of WWNs that each port is willing to see, and it's first-come-first-served, and the blaades that show up later never get a chance.

A similar configuration in a different DC is working fine... but that site has Brocades, not Ciscos, and the enclosures in question are running OS9, not 10.  I've tried to duplicate the setups but I'm obviously tripping over something.

Is there anything obvious that I could be doing wrong?  Should I be using multi-switch mode, with the ports in E mode instead of F?