Experience Cloud can be used for employee apps, such as an onboarding app for new hires. However, there are some considerations when creating an employee app, such as:
Not all Chatter posts inside Chatter groups within the employee app will be available in the main org. Only posts in public groups or groups that are shared with the main org will be visible in both places.
Chatter posts related to a record will be available in the employee app as well as the main org. However, users need to have access to the record in both places to see the posts.

To share records with Customer Community users using Sharing Sets, you should create one Sharing Set and add the objects to share in the Sharing Set. A Sharing Set is a feature that allows you to share records with Customer Community users based on common account or contact fields. For example, you can share records with users who have the same account ID or contact ID as the record owner. To use Sharing Sets, you need to create one Sharing Set and add the objects that you want to share in the Sharing Set. You can then define the access level and criteria for each object.

To differentiate between the leads created by partners and the leads created by its own Sales team, UMS should create lead record types and page layouts for lead distribution. A record type is a way to offer different business processes, picklist values, and page layouts to different users based on their profiles. A page layout is a way to control the layout and organization of detail and edit pages in Salesforce. By creating lead record types and page layouts, UMS can customize the fields and values that are displayed to partners and Sales team members.

The Embedded Service component allows you to embed a chat window in your Experience Cloud site, so customers can chat with agents while browsing the site. You can add the Embedded Service component to any Builder page and configure its properties, such as the chat button label, pre-chat fields, and offline support.

To grant Experience Builder access to two colleagues who will be responsible for creating and managing new microsites, the system administrator should grant Publisher and Builder roles. Publisher and Builder are two Experience Builder roles that define what users can do on the site. Publisher is a role that allows users to add contributors, publish changes, and activate or deactivate sites. Builder is a role that allows users to create and customize sites, but not publish them.