pull out data from database and display in Gravity form

1) I'm using s2member plugin on my wordpress site which creates a membership site and stores profile information in the database. Can I pull out any data and display that in a gravity form using php. is so, how?

You could pull out information, but we couldn't help you create that customization. You'd have to hire a developer to help you.

2) Is it possible to store any gravity form data in a database after user submits the form?

Gravity Forms does store the data in its own database tables by default.

3) After the user submits the form, can all of the data be exported to a pdf file and emailed?

You can use a third party add-on to help with that: http://wordpress.org/plugins/gravity-forms-pdf-extended/

4) If a user finishes only half of the form, can he go back to it at a later date to finish filling it out?

You can use a third party add-on to help with this as well: http://wordpress.org/plugins/gravity-forms-data-persistence-add-on/

No problem. All my best!