Trying to be slightly realistic is hard... so this took me 45 minutes!
#4 Privet Drive ($59.99)
Set: Much like The Burrow set from 2010. Bottom Floor could have the kitchen (cabinets, counters, drawers, etc) and the living room with a TV and basic furniture, with some plates and various foods on the table. The Second floor could have Harry's room (with Hedwig bed, nightstand with lamp and a picture of James and Lily in LEGO form) and a portion of the hallway. The front of the building would have uniform plants, with a chain-fence and lamp-post with a light gray car, much like the magic car from like the one from 2010's Hogwart's Express, but slightly more modern and done in light gray bricks.
Minifigures: 6, just like i]The Burrow[/i]-- Harry Potter in a NEW outfit (please no more blue-jackets!), Petunia, Vernon, Dudley, Kingsley Shacklebolt (I'd love to get him in LEGO!), Tonks (if only...) or a new Alastor Moody
Animals: Hedwig, grey owl
The Ministry of Magic ($129.99)
Set: Think of it as being like the Hogwarts Castle set from 2010 with the whole folding thingy. Section one could have the Flo Network fireplaces where Voldemort and Dumbledore dueled and the london phone booth on the lower floor, with Umbridge's office up top, with ugly pink furniture with kittens and what not. Section two could be the court room, seen in movie 5. Section 3 could be smaller with three floors, with each room dedicated to one of the departments. The last and biggest section could have the department of mysteries, with toppling skinny shelves with the prophecy orbs as a play feature, then the room with the veil.
Minifigures: Harry in uniform, Hermione in Uniform, Ron in Uniform, Cornelius Fudge (with bowler cap!), new Dolores Umbridge, new Sirius Black, NEW Lucius Malfoy (please!), Dumbledore, Voldemort, and Bellatrix Lestrange, and 2 more members of the Order of the Pheonix. <--(I know it's a lot, but there's always hope!)
Animals: A larger, printed snake to be Nagini.
Rescuing Sirius ($39.99)
Set: Another add-on to Hogwarts. A rectangular tower with a closed cell for Sirius on the top of the structure. The roof (one of the sand green ones from the older HP sets) would be detachable to take our sirius easier. There'd be a small bench and mug. Beneath the top level could be the room of requirement of another Hogwarts room.
Minifigures:Harry Potter, Hermione Granger (with time-turner printed on torso), Sirius Black in prison garb, and 2 Dementors
Animals: BUCKBEAK!! (with printed wings, feathers and eyes)
Herbology Class ($39.99)
Set: Green housethat can fold open. Inside are a few tables with pots and generic plants with various colored flowers. Of to one side of the green house would be a longer table with plants. The windows on that side would have opening windows, to mimic Slughorn stealing those snippy plants from movie 6. To the other side of the room would be other magical-like plants with a few mandrakes, whose bodies could the mini-minifures from the LEGO Games line.
Minifigures: Harry Potter, Neville Longbottom (with reversible face that has a passed-out expression), Professor Sprout, and Horace Slughorn (I want a minifigure of him sooo bad!!)
Meeting Buckbeak ($11.99)
Set: A small tree with a new and printed Buckbeak with 2 crates for water and one with two chicken legs.
Minifigures: Hagrid, Harry Potter (Draco?)
Animals: Buckbeak