Properly delete data forever and free up the space it was using?
The first step is worthless because delete operations are completely logged.
Use truncate instead if you want to empty a table.
About the task 4 you have to reorganize pages because the release pages free only pages ad the end of the mdf file. It will takes a lot.
I suggest you add task 5: rebuild the indexes because shrinking the data file causes the indexes to fragment.