2. Obtain new set of licences for features in Cdot and a cluster licence.
7-Mode 8.2 and C-Mode 8.3+ are using the same node-locked feature licenses. Quoting Data ONTAP Licensing :
In Data ONTAP 8.2 and 8.3, the only new license key required to build a cluster is a Cluster Base Key, which you can request through your Sales team. For licensable Data ONTAP 8.2 features, the same license keys used for 7-Mode are also used for clustered Data ONTAP 8.2.