In April 2015 I decided to get rid of my Facebook profile. I first downloaded a report to see what they had about me and then deleted the profile. One can assume that the good people that work there keep their promise and delete the profile.
I am currently working on a slides for a presentation about securing your Facebook account and setting up your privacy settings as restrictive as possible. Since I had no account I needed to make a temporary account, with a fake first and last name (I know against the EULA), and used the same e-mail address than the account deleted in April.
One can suppose that the 'old' data is gone but interestingly every friend Facebook proposes was in the friend list I had before.
I can only come to one conclusion and that is that they do not actually delete everything otherwise those friend proposals should have been random strangers (maybe living in the same town).