Vendor Permissions For Addon

I think you are confusing the standard Vendor Plans addon with the new Vendor addon (not sure of the name) that adds additional functionality but comes with a hefty price tag. Not familiar with any Vendor Tabs addon from cs-cart. Must be from 3rd party.

Yes, you are right. The new is Vendor Privileges. Mea culpa. As for the other, I said it's "fourth-party"

This is the Vendor Privileges

$schema['vendor_privileges'] = true;

return $schema;

That's the metrics schema. I've not had call to use it but my guess it it allows vendors to collect their own statistics for sales, etc.