just ask them
There is no secret blood relative of Harry's revealed in Harry Potter and the Deathly Hallows.
In my opinion the biggest secret is that Severus Snape is good.
The order of the Pheonix
Their is no Harry Potter and the DA. DA is a term used by some of Harry's classmates to refer to Dumbledore's Army, the secret organization, run by Harry to teach the students Defence Against the Dark Arts. This club is formed in Harry Potter and the Order of the Phoenix. Harry is 15 in this book/movie and therefor to young to get married even if he wanted to at the time.
Please see the following walk through for details on the secret areas. http://www.gamefaqs.com/pc/562014-harry-potter-and-the-chamber-of-secrets/faqs/55157
There are several walkthroughs on Game FAQ's that can help you find the portraits.
Yes
After you finish the last task in the Harry Potter and the Order of the Phoenix video game, which is finding Luna Lovegood's hidden possessions, you may still have 40% or more or less left. To finish 100%, you may get all the trophies in the Room of Rewards, unlock all secret passages, get all the passwords of the portraits, etc...
There is no secret blood relative of Harry's revealed in Harry Potter and the Deathly Hallows.
There is no cheat code to open all the portraits. You will have to approach each portrait and do what they are asking.
You have to find a replica of a portrait that is awake. then you have to preform a task so that you can use the secret passage way behind it.
a sword
In my opinion the biggest secret is that Severus Snape is good.
Secret!! :p
get married and have 3 kids
He is a werewolf, and that he was best friends with Sirius Black and Harry's dad (James Potter).
Harry opened the secret passage with Parseltongue.