for the first part -
report on Incident table with a filter for assignment group = x
I'd start with a list view to make sure you're getting the right data. Then I'd switch to a trend chart and use the following settings.
You'll get a chart view with a count of incidents created by day assigned to that group. You could also add a Group by State so you could see the state of the incidents.
(you may want to add a filter to only show active incidents OR show only ones created in last 12 months, otherwise you'll have too much data to display)
For the second part I'm not sure what you're trying to display. what do you mean by outflow?
