As you still see the upgrade buttons for EE modules, the enterprise modules are still not available to the odoo instance. Did you add EE addons path to odoo configuration file ? If not, add enterprise addons path in odoo conf file and restart the odoo service and click on update app list.
Recently Odoo has changed the pricing policy and from now on the charges will be based on users(not based on modules).
You can create module depending on enterprise module by respecting the odoo enterprise license.