1. No, the only windows would be the same ones where the dashboard is also unavailable.
2. The dashboard maintenance windows are published on the dashboard ahead of time. There may also be a way to get emails, but I'm actually unsure of this. Someone else may know. They do send them for firmware upgrade windows, but I don't recall seeing one for overall outages.
3. I'm not aware of an endpoint that shows this.
For an unscheduled issue you may be able to use the various ways the status page is published to create your own integrations. There are RSS, Atom, and Slack options: https://documentation.meraki.com/General_Administration/Monitoring_and_Reporting/Meraki_Status_Page
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