I have posted an answer to this question:
Assign a workflow task to the user who triggered the workflow rule
The original asker has now updated the question with more information, which will significantly change my answer.
I'm torn as to whether I should edit the answer I have already posted, which is (mostly) still valid, but I could change significantly, or whether I should just post a new answer which is significantly different from my original answer.
I'm leaning toward removing irrelevant information from my first answer and posting a brand new one.