To answer your other questions:
Q1: Can we register multiple instances of VSC with vCenter with no issues?
A: This is not recommended. Some VSC operations require object locking which is only enforced across one VSC instance.
Q2: How would one go about migrating existing VSC Backup Job defniitions to a new server?
A: The steps in my post above will copy these. They are located in VSC_INSTALL_DIR\smvi\server\repository.
Q3: Is there an easier way to move VSC to a new server?
A: Hopefully, the steps in my post above simplifies the work for you to move VSC to a new server.