Canadian API expose

I am evaluating QuickBooks Online Simple Start + Payroll Core for my business located in British Columbia, Canada. My sole requirement is the ability to programmatically execute our semi-monthly pay runs via a custom CLI/machine interface.
Before purchasing the software, I need technical confirmation on two specific API limitations:

Tier Gating: I understand that standard Accounting endpoints are open to the Builder tier. However, can a private, internal-use app access the Payroll API without upgrading to the Silver tier ($300 USD/mo) of the App Partner Program?
Write Capabilities (Canada): Does the current Canadian API expose mutation endpoints that allow developers to programmatically trigger and process a final pay run, or are the Canadian Payroll endpoints strictly limited to read-only functions (e.g., retrieving compensation data and timesheets)?