For a Satchmo project we have to change the fields a customer has to fill out during checkout. Specifically, we have to:

• Add a 'middle name' field
• Replace the bill and delivery addressee with separate first, middle and last name fields
• Replace the two address lines with street, number and number extension

These fields are expected by an upstream web service, so we need to store this data separately.

What's the best way to achieve this with minimal changes in the rest of Satchmo? We prefer a solution in which we do not have to change the Satchmo code itself, but if required we can fork it.