I think the Doors are deliberately misplaced, the artist has taken license to rearrange them so the maximum number of exits can be shown in each shot.
- The backdoor has been moved to the side of the house so you can see it in the same shot as both the neighbours yards, the backyard and the tree house, when otherwise you'd probably need 3 separate turn shots to take in everything.
- The same goes for Tiff and Marys doors no way they would be next to each other in a house like that, but because of the artistic license you don't need 2 separate screen loads to check both doors and the stairs.
- And the door to the extension/mystery room has been pulled forward from it's most logical position, hidden under the stairs.
I think the MCs room is similar, if you look at Marys room it doesn't seem big enough to take up the space above the garage and kitchen (the garage alone most likely), the space above the kitchen is probably the MC's room, maybe a half floor up to accommodate high ceilings in the kitchen, making it half in the attic space, which might explain casement windows toward Sara's house and overlooking the backyard. (of course this would make the orientation of the window in the screenshot from
Count Morado's post backward)
but of course the Tardis Theory is still valid. Artistic License being Artistic License.