I have (had) a number of ghost z-wave devices on my C7, and was told that they can have an effect on migration to the C8.
The other day I started with 10, and now have reduced it to 3 (which are being very stubborn).
0x13 is definitely still powered up. You can take your hub elsewhere (a friends house) then do the remove. (not the hex numbers and make sure the hub is on dhcp so you can work elsewhere) then do the remove. If that doesn't work you will need a z-wave stick paired as a secondary controller to remove them.
Soft reset really can't hurt anything -basically you download a local backup that will contain the hubs database (which can clean up any issues that might be existing in the database), do the soft reset, and then restore the backup you downloaded. You end up back where you started, and any odd jumbles that might have been in your database should be gone. Of course, if your database is already OK, nothing will change.
For the soft reset/restore you can now (since a few major versions ago) just create a backup and then immediately restore it. When you do a restore it automatically does a soft reset first. Skips having to go into the diagnostic tool that way. If you want to clear all past logs, you need to go through the diagnostic tool.