1) That code is a bug it should not be added, and can be removed. i have logged a bug in our system
2) Inserting the form does not insert any of the server behaviors, you would needs to add the server behaviors needed for express checkout.
on the checkout page you would add the Express Checkout Authentication server behavior, you should also need to create the pp_confirm page and add the Get Payer profile and Process Express Checkout behaviors.
i would suggest running the checkout wizard to create express checkout pages to get familiar with how the pages are put together.
3)
Again with the Insert Checkout server behavior 
you misunderstand that access point, it is not a server behavior, it is only there to insert the checkout form, you need to add the server behaviors to the page that use the checkout form
this includes the create email message, store order summary / details, and the server behaviors to process the cachet through the gateway.
those behaviors are normally added to the conform page.
