Hub C8 shows a link back to itself. Is this normal

[bertabcd1234]

Assuming your question isn't the same as this: seemingly yes.

Why zwave graph shows ghost but nothing in the device list in HE and Simplicity Studio?

What ghost? I see a loop in your Z-Wave graph from the hub back to itself. That seems to happen for some people for whatever reason but is not known to be indicative of any problems.