When you package your Experience Cloud site, some components and settings are included as dependencies, while others are not. For example:
Custom list views for custom objects are not included as dependencies. You need to manually add them to your package or recreate them in the target org.
Custom list views for standard objects are not included as dependencies. You need to manually add them to your package or recreate them in the target org.

External Apps is a user license type that allows users to access up to 10 custom objects per app and unlimited standard CRM objects. This license type is suitable for the researchers who need to access at least 20 custom objects for the coffee company's solution.

Data Category Visibility allows you to control which Knowledge articles are visible to which users based on data categories and user roles, permission sets, or profiles. You can assign data category visibility at different levels, such as the org-wide default, the role hierarchy, or the permission set.

To meet the requirements for both personas, GCC should create a portal for external researchers and give internal staff access to the main org. This will allow GCC to provide different features and permissions for each persona, as well as enable collaboration between them in a private Chatter group. For example, GCC can create a portal for external researchers using the Partner Central template, where they can view and update financial data, access reports and dashboards, and join Chatter groups. GCC can also give internal staff access to the main org using standard user licenses, where they can manage portfolio data, create workflows and processes, and join Chatter groups.

To fix the issue of Experience Cloud users not being able to view Contacts and Accounts, you should configure sharing rules on each object to give Read Only access to Experience Cloud users. Sharing rules allow you to extend sharing access to users in public groups, roles, or territories. You can use sharing rules to grant Read Only access to Contacts and Accounts owned by internal users to Experience Cloud users.