This is a question that comes up frequently. For most objects, they can not be renamed. Since the object DN is used thoughout the ACI Architecture to uniquely identify objects in the system. Changing the name of an object may cause issues where this name may be referenced elsewhere in the ACI Fabric configuration. So, the object needs to be removed and re-created with new name.
If removing objects to rename objects make sure that you export your configuration "prior" to any changes. Schedule a maintenance window to make the changes. Make the desired changes and then verify configuration is working after the change.
You should not need to use an Attachable Entity Profile for APIC connectivity. The vPC between APICs and leafs is brought up automatically and doesn't require user configuration.
If you wanted to do something like what you mentioned, you could write a script to delete the associations to an object, delete the object, create a new object with the new name, then create the new associations. However if you are doing that with static paths and vPCs for example, there will be some down time associated with it. So you would need to take your specific network configuration into account when designing a script to "rename" objects.