Correct, there is no service console on esxi, however you still need a network for vSphere vCenter Server / Client connections.
Are the iSCSI connections also on the same subnet as everything else?
Are you able to add another switch or even get your current switch ports in a vlan for vmotion etc?
Ideally you want to have each of these on separate switches or vlans. If you could add another switch, placed in the rack somewhere and have private networks for vmotion and iscsi, etc, that would work.
