PayPal Express, saving order and email receipt

I've modified the profile on our site to contain a couple of special fields. We're using PayPal Express for checkout. When the user returns to our site and submit the order it's saved and a receipt is generated.

I'd like to modify that process a little so that they're encouraged to complete those fields on the profile and then they are captured and included in the receipt and if they're missing, they'll get a notice that they should complete them.

Could I schedule a session of custom assistance to help me with this? Or could you point out where the order is saved and where the receipt is generated? I'm hoping it's in that order...

Would it be easier to have a custom field which gets sent to Paypal and comes back again? I was surprised that the user doesn't fill out a profile on the site before going to PayPal, as that's how other sites I've done were ordered.

Do I need to do something to get this scheduled? Of course everyone has their hair on fire, so I'd like to get this done.