I'm not sure what you mean for your first question.... there are a ton of regular pep files in the database, so I'm not sure why you'd want to create more work for yourself by converting a foam file back for paper use.
For your second question, put the pep visor onto your model to help keep it square and sturdy during your resin and fiberglass steps.
Third, do you mean the bicep armor he has beneath the commando shoulders? If so, all the reach bicep armors are the same, just with different attachments. If you did mean the forearms, same thing. He has reach forearms with a tac pad attachment.