Welcome
Icinga is a blank monitoring canvas/framework with a lot of flexibility and resulting edge cases and paper cuts - it’s the Lego of monitoring.
In broad strokes, you have 3 major ways to get going.
- get a consultant or Icinga GmbH to help you set it up Icinga » Partners and train you
- Do it your self by experimenting, using the documentation and asking here about your specific sticking points
- Use a configuration tool like Ansible with the LFOPS Roles that has the best practices for the setup build in, to get going fast but you still need to learn how to use the resulting system.
A mix of the above is also possible and maybe the right approach for you.
about your question:
- Satellites aren’t well supported in the director and need manual setup. I would go for a satellite per location. Avoid HA for master and satellites if possible. Use agents on Windows and Linux endpoints to distribute the load and make HA less important.
- use a plugin collection like Linuxfabrik’s monitoring-plugins to have similar checks for both OSs and prepared templates
- This is IMHO a unsolvable problem and can only be managed. I will go with the criticality and team setup from the Linuxfabrik.
Disclaimer: I’m a happy customer of the Linuxfabrik 