Need to make changes to Job Form

These are more along the lines of requests than issues:

1. I want to make it possible for non-logged in users to post a job. I had edited out the login check in the php page but then an “undefined” message came up under each field when filled in. Ideally, a non-logged in user would be able to fill out the form but also register at the same time. Form details would not be submitted until registration is complete. How could I do this?

2. Your form fields are created in a complex manner. Quite impressive coding. But what happens if I need to add fields or make some fields optional instead of required? How can I accomplish this?