Photo editing to replace person in photo, including radical reconstruction to accommodate the changes

"This is a photo of me (pic on left) with my research mentor. A photo was also taken with a visiting professor, which to my dismay, turned out to be a dud. Unfortunately, he has now left the country and I don't have the opportunity of being pictured with him again. However, here is a photo of him (pic on right). Would you place him in the first photo with me please. In fact , can I ask you to place him a bit behind me (to the side)? But that will mean reconstructing my hidden arm... It's a lot to ask. But is it possible?"