How to find password of all portraits?

Fat Lady: The Prefects of Gryffindor, Ron and Hermione, are told on the train, but as you (Harry) and Ron confront the Fat Lady, you will discover that Ron has forgotten the password. Ron suggests that you ask another Gryffindor student. The Gryffindors are the students with red stripes on their uniforms. Just ask one of these students and they will tell you that the password is 'Mimbulus Mimbletonia', such as in the book.
Basil Fronsac: Basil will instruct you to ask a Ravenclaw student where Rowena Ravenclaw came from. Ask any student and they will tell you that she was from the glens. Return to Basil's portrait and give him the information. He will then tell you that the password is 'Studious Success'.
The Owl Wizard: When confronted, he will ask you to get the current Daily Prophet and tell him the headline. Once prompted, he will suggest looking in the Great Hall, where owls go in and out with newspapers. He doesn't know how to make the owls give you the newspaper, so you're basically on your own. Go to the Great Hall and to the owl reading stand at the front. Preform the Accio charm on it and it will go to a cut scene showing four owls swooping down, one of them (presumably Hedwig) dropping a Daily Prophet on the nearest table. Pick up the newspaper and Harry will read the headline out loud. Then return to the Owl Wizard and give him the required information. He will say that the headline is boring (despite the fact that it is a death) and tell you that the password is "No news is good news". Please note; The owls will only come down if the sky is turned off using Depluso and the candles are put out.
Giffard Abbott: Giffard favours Hufflepuffs, and, like Basil, it is required to ask a Hufflepuff the password. Since you helped Cedric Diggory last year, any Hufflepuff (the students with the yellow stripes on their uniforms) will be happy to inform you that the password is 'Dragon's Egg'.
Damara Dodderidge : Damara is starving when you first speak to her, and will ask you to go down to Giffard and tell him that she wants some food sent up. Go talk to Giffard, and he will ask you to tell her that he will see what he can do. Deliver the good news to Damara, and she will tell you that the password is 'Chops and gravy'.
Percival Pratt: This portrait loves to rhyme, and will tell you to "Seek the man with faces three" if you want to know his password. The portrait in question is on the seventh floor, of a black-robed man who also guards a secret passage (but we will speak of him later). He will say that he doesn't know the password, but to talk to Basil. Do so, and Basil will send you to the shepherdess. The shepherdess is difficult to find, but she is on the second floor. Just look around and you'll find her, she isn't difficult to miss because she often shouts out comments to passers-by. Once you speak to her, she suggests that you talk to Google Stump. Google hangs in the Viaduct Entrance, and since he is the only portrait there (he, too, guards a passageway) he is easy to find. Finally, he will send you to Giffard, who, thankfully, knows that 'the password is absurd'. Go back to Percival, and he will gladly lead you to the boathouse.
Nervous Gentleman: The Nervous Gentleman is in the Herbology Corridor and is across from the portrait of an eye. Anyone would feel awkward being watched by an enormous eye. All you have to do to soothe him is to cast Reparo on the two broken suits of armor on either side of the eye. The eye will be covered up by a Gryffindor banner and the Nervous Gentleman will thank you by telling you that his password is 'Flaming earwigs'.
Google Stump: If asked, Google will share his password with only you, and only you. Google instructs you to rid the Viaduct Entrance of everyone around, so just hold you wand up at the students (or if you've learned Stupefy, you can cast that on the students). They will run away. Confront Google again and he will tell you that his password is 'Volo futurus unus' (Latin for 'I want to be one').
Boris the Bewildered: Boris has not heard his password in fifty years, in fact he's forgotten it. Now you have to rediscover it by asking anyone who was at Hogwarts fifty years ago to tell you the password. Though Hagrid does come to mind and Dumbledore, it is neither because it is truly Myrtle you have to ask. Since she has a crush on Harry, she will tell you that the password is 'Forget-me-never'.
The Man With Faces Three: This man wants you to find 'himself' in another portrait. What he means his to find the other door of his passageway. This is on the fourth floor and is covered in cobwebs. Burn the cobwebs away with Incendio (if you have not learned the spell yet, you will have to wait until you do) and talk to him. He will say that his password is 'Three heads are better then one'
The Astronomer: Hannah Abbott on the dungeon level will not come to the Dumbledore's Army meeting unless you find a passageway to get her there safety. The passageway is simple, since it is nearby and you merely have to ask the Astronomer his password. He will tell you that his password is 'Scurrilous scoundrel'.
The Slytherin Witch: This portrait of a rather nasty Slytherin Witch only lets through the Slytherins and those who know the password. She suggests that you ask another Slytherin student the password. Since you know very well that Slytherins will not tell you something that people outside Slytherins should know, there is only one way to get this password; Eavesdrop. You must have completed Ginny's quest to get the Doxy Venom from Umbridge's office to do this, therefore unlocking the privilege of the Invisibility Cloak. Go get on your Invisibility Cloak and go back to the Dungeon corridor(at the end of the grand staircase). Two Slytherins will be there, discussing how they will be late for potions unless they use the passage way. Follow them to the portrait. Once they are there, they will tell the Slytherin Witch that the password is 'Slytherins are Supreme' then the witch will say and be extra nasty to mudbloods, followed by many laughs. Go take off your invisibility cloak and return to the corridor. Tell the Witch the password, and she will grudgingly let you through.