1.) This is set in System Settings >> Task Completion Reporting Policy. This email shows items where the reported % completion is less than the expected % completion (essentially everything users should be reporting progress on).
2.) This is a notification set in System Settings >> Time Tracking. I usually turn this off since it is a simple reminder to report time. If you are utilizing time tracking that it should be part of a daily process, so I find little value in this notification. It will go out if there are any items in the past week where time could have been reported and time was not reported (so it will pretty much trigger every week).