Hi Mae-1480,
According to the research I have done, these accounts would still count towards the user limit because the licensing requirement is around "accounts" and not just users. https://www.microsoft.com/en-us/Licensing/product-licensing/products
For previous versions of Windows Server Essentials there was a way to "hide" accounts used for services from the dashboard so that they are not counted towards the licensing limit, but I believe that with the current version the only option is to upgrade to the Standard tier. You can make a feature request on the Windows Server product page to confirm though. https://windowsserver.uservoice.com/forums/295047-general-feedback