Hello,
As stated, I would suggest you go through the Licensing guide (go.microsoft.com/.../. Appendix D on Page 49 explains in detail the custom entity usage:
".... 1. Create and modify up to 15 additional entities (custom entities or “out-of-the-box” Common Data Service entities) per app module for Team Members.
2. All customization must be per pre-approved application scenarios in Appendix A.
3. There is no limit on read rights for Dynamics 365 custom entities
4. Full CRUD on data records associated with custom entities...."
Also please note Appendix B note:
"...To configure and administer Dynamics 365 services a full enterprise user license is required (Sales, Customer Service, Field Service, Project Service Automation)..."
I suggest also to review the information related to Team members and the recent changes, here an extract of the public information:
"Users who have existing Team Member licenses purchased during or after October 2018 will be restricted to this set of designated apps; these users will no longer be able to access Customer Service Hub, Sales Hub, or custom apps.
During the early-access phase of the new Dynamics 365 Team Members license, users who have the new license will be able to use the designated Team Member apps in addition to all existing apps. However, after license enforcement is turned on with the 2020 release wave 1 build, apps that users aren't entitled to use—such as Customer Service Hub, Sales Hub, and custom apps—won't be accessible to them. We recommend that you test your Team Member scenarios and migrate any customizations to the designated apps as needed.
To facilitate a smooth transition, all customer organization instances that are created before April 1, 2020 have been granted an additional grace period until January 31, 2021."
Link for reference:
docs.microsoft.com/.../team-members-license
Hope this helps!
Yader.