Don't think this really answers your questions, but I've always done one update per policy for cleanup purposes.
Once a month I go to the superseded report, and any policy superseded, I move it to a "disabled updates" folder.
Once in that folder, it's easy to disable all superseded updates at once. Then I wait at least a day and delete the policies in that folder.
At some point during the month, I run superseded report again, right click on all superseded reports (which now show downloaded but not in a policy), right click and do disable. This queues server to delete them.
I used to diligently then check server space, then run Check Software Update Package Integrity and when that completes confirm patches disabled and server space was freed up. Now I normally just let it run at the scheduled interval (once a week) as it's been working as expected for quite awhile.
As far as I know, 8.1 doesn't change anything with patch cleanup.