Since you need to sort & rename the fields, the best option will be the Sort Component in the Data Flow task (like you mentioned) . If you only want to rename columns, then use the "Derived Column" component. The Sort component should look as follows: In my example, you can see the LastName, FirstName & BirthDate are sorted and LastName & BirthDate are renamed.
The Data flow task should look like this:
Note : Sorting operation can be done in the database using SQL scripts (stored procedure) so it is advised to use SQL for better performance.