Workflow tasks (almost) always require user interaction. The only exception to this is confirming workflow tasks via .NET/REST API.
All your described ideas are not possible with default system behaviour, but you could implement any of them using custom programming via the API.
Even Autoindex is not able to confirm a workflow task - it can only change index entries, which has no effect on already open tasks.
Hope this helps.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant