Screen shots aren't really going to help here, they don't show the full picture.

What does you dataset that SSRS look like, are you able to provide sample data...

Looking at your SQL I wouldn't have expected it to give me 3 duplicates, and it didn't when i tried.

This sounds like you've possibly triplicated your data in...

Yes, there is a property value on your task called DelayValidation. If you put that the TRUE, it won't check until it gets to the that task in the Task...

Duplicate of topic https://www.sqlservercentral.com/Forums/1853363/SSIS-package-running-very-slow. Please only create one topic per problem.

I'm impressed that runs, you're basing logic on a non aggregate field, and then attempting to do an aggregate.

Either of these examples should work, depends on your preference....

You can join on many tables, that's not a problem. So, you could easily have a query that looks like:
SELECT E.Name,
       D.Department,
       ISNULL(J.Name, 'No Assigned Role') AS...

The error is showing that someone has the file open. Do you have it open in Excel, could someone else? Also, ensure the files aren't passworded.