Question about the Asynchronous Throw Message Event

Hi There,
I have a workflow definition like this:

Two questions related with this design:

  1. Currently i config all the “Send Mail” events as “Asynchronous Before” for making sure the main flow still work even the Mail server is down, but the “Send Mail” in Subprocess could not be triggered with the Asynchronous setting, is there anything wrong with it?

  2. When the mail server is down, the Send Mail will throw incident, according to the documentation that incidents will stall the execution and will require manual intervention to continue
    (Incidents | docs.camunda.org), want to confirm that does the incidents will impact the whole workflow?

I also want to know is that feasible Camunda could support the feature like Main Workflow with external service but the service won’t impact the main whether it is available or not:

Thanks!