Please find my answers below.
I would also recommend joining one of our Q&A webinars. Our CSM members will be able to work on the report during the session and by asking additional questions help you find the right output.
1) the report pulls through duplicate tasks and tasks that have been deleted from the project.
Please create a filter to include only active tasks (using State field - Active, Cancelled, Completed, Draft, On Hold)
2) the base line work pulls through the duration for the whole task not the duration for the individual assigned to the task.
Please try using another field: <assigned.link> Work. I would also recommend using the <assigned.link>. to pull more information regarding the task. Using the Task object might cause the duplication you mentioned.
Please let me know if you have any further questions.