Comprehensive and Detailed Explanation:
To efficiently monitor social media platforms and convert relevant interactions into cases, leveraging a third- party application from the Salesforce AppExchange is recommended. These applications are designed to integrate seamlessly with Salesforce and provide robust social media monitoring capabilities.
From Salesforce's best practices:
"With the right social media monitoring tools, you can create an automatic ticket that your customer service team can see and respond to immediately, and match it with that customer's inquiries by phone, email, and more."
-Salesforce Marketing Cloud
Utilizing a third-party app ensures that UC can quickly implement a solution within the two-week timeframe, providing the necessary tools to monitor social media channels effectively and manage customer interactions through Salesforce.

The Case Lifecycle report tracks the time a case spends in each ownership status-ideal for measuring how long cases are owned by specific teams or agents. This report helps identify bottlenecks and efficiency issues across teams during the case resolution process.
Option A (Historical Trending) tracks field value changes over time but not ownership duration.
Option C (Milestone report) is specific to SLA tracking within Entitlement Management, not ownership tracking.
Referenced Salesforce Materials:
* Service Cloud Consultant Exam Guide - Contact Center Analytics Domain.
* Salesforce Help: "Use Case Lifecycle Reports to Measure Case Duration by Status or Owner."
* Salesforce Trailhead: "Analyze Case Ownership and Lifecycle Metrics."

For supporting attachments up to 25 MB and handling under 2,500 inquiries per day via free-form email, On-Demand Email-to-Case is the recommended solution. On-Demand Email-to-Case processes emails and attachments without requiring an email server, and is suitable for the specified volume and attachment size requirements, ensuring efficient case creation from customer emails.

To track the efficiency of individual agents using the Service Cloud Voice Dialer, focusing on the "After Conversation Work Time" metric is recommended. This metric measures the time spent by agents on follow-up tasks after a call has ended, providing insights into how efficiently agents manage their post-call responsibilities and contributing to an overall understanding of agent productivity.

To accommodate the common stages and fields for new product support cases and the additional stages and fields for maintenance cases, implementing Support Processes is recommended. Support Processes allow for the customization of case stages based on the type of support being provided, ensuring that all necessary information is captured accurately for each case type.