In short, yes. (question 1)
You don't want both organization non-editing teachers to get ALL notifications. Organization 1 should not see results for students in Organization 2. This is why you would use groups.
An email will send regardless of attempt number or status. Unfortunately, there isn't a way to separate that--teachers/non-editing get submission messages either via email or internal messaging regardless of attempt number or status. There might be a way to include something about attempt number and grade BUT you would have to do some serious work on modifying the message. Moodle docs does not include any info on those particular settings--only including links to look at results.
You don't want both organization non-editing teachers to get ALL notifications. Organization 1 should not see results for students in Organization 2. This is why you would use groups.
An email will send regardless of attempt number or status. Unfortunately, there isn't a way to separate that--teachers/non-editing get submission messages either via email or internal messaging regardless of attempt number or status. There might be a way to include something about attempt number and grade BUT you would have to do some serious work on modifying the message. Moodle docs does not include any info on those particular settings--only including links to look at results.