I'm looking for some guidance on assigning IP addresses to UCS-E. Can the CICM be on the same subnet as the kernel and the host? Is it required, or best practice, to have them on different subnets?
All the questions you pose are really based on your design requirement. Typically you would have OOB management on a different subnet than data traffic, however, it is not required. It just depends how you want to segment traffic and if you have available infrastructure.
I would take a look at the configuration guide, as it outlines most best practices and step-by-step config:
