Photoshop a photograph to add extra imagery elements

I would like someone to swap 5 of the postcards and samples seen on this photo (a copyrighted professional photo of our studio) to show images of our work and sketches, as a snapshot of our studio and creative processes - the first one (blank blurry page), the one with the lion, the black and white one of the lady, the bright blue one at the bottom and the dark blue one at the top.

The added elements must be treated with all the depth of field, blurring and sharpness as captured so well in the original photo, so the final image looks as realistic as possible.

You must also provide the layered PSD.

Here is the image as a screengrab - hi res one will be provided.
https://www.dropbox.com/s/bqypo8eg6oip95z/Screenshot%202015-08-01%2013.47.57.png?dl=0

Many thanks
Caroline