How do you 'manage the funnel'?

Part of Cloud Kicks' solution design is to incorporate Lightning Experience. The Consultant wants to see if there is an increase in the number of Lightning users. How should a Consultant track this?

The admin at uBHMBon tamers has been getting complaints from sales reps about duplicate Leads ... Salesforce. The admin has already set up a matching rule for Leads.
What should the consultant recommend to resolve the issue?

Universal Containers is analyzing data to identify gaps and wants to know which Accounts with open Opportunities are missing Contacts.
Which feature should a consultant recommend building this report?

Universal Containers acquires sales leads each year through trade show attendance by its sales and marketing employees. Occasionally, duplicate leads are generated when the marketing team imports leads that already exist in the system. What should a consultant recommend to prevent duplicate leads in the system?