Determine the accurate chronological progression concerning the formal elevation of these specific geopolitical entities to full statehood status:
1. The northeastern territory of Nagaland secured full statehood prior to the integration of Himachal Pradesh.
2. The territory of Tripura achieved its status as a constituent state during the same decade as Himachal Pradesh.
3. The territory of Mizoram was granted full statehood earlier than the formal integration of the Tripuri kingdom.