I don't directly know the answer to your question. I hope someone else who knows more about this can chime in and educate us both.
But with how Apple views privacy I would assume that a wipe is definitely a wipe through and through so you can't simply just jump into old data.
The only way I can think of to retrieve old data is by restoring from a backup that had the information you seek but that requires the login/password that you don't have.