Thank you for your reply!
All I'm really going to need is
2 checkboxes (one for Delivery/pickup, and one for if the delivery is a surprise),
delivery address, recipient name, recipient phone number, delivery datetime, and custom message.
I overwrote the checkout form.html and contact/_contact_info_form_shipping.html.
In _contact_info_form_shipping.html I added my own "delivery" items, (the things I listed above), but then pressing submit button wasn't working (probably because the form isn't filled out properly?) so I figured these items also had to be a part of satchmo_store/shop/models.py so I added them there but now I'm getting the database error :/