I will take snapshots of the images at every stage of processing that you want to export by clicking on the + button on the left panel. Afterwards, click on each of them and export.
Let me explain in more detail. You first process the image fully and resize to 900px. Take the first snap shot. Then go back to resize module and resize to 500px. Take the second snapshot. Now change the profile to Neutral and crop the photo to your taste and resize to 500px. Take the third snapshot. You can now go to each stage of processing by clicking on those snapshots and export. You will have three images with three different pp3 files.