Steve757 is right.
The thing about photo shoots is that it's like your family. When you want to take a picture of them, you get them all together, then you tell them to move in close, so you can get all of them in the frame.
It's the same with aircraft. It's that desire to get them in close together for the right shot, that can get you in trouble. If you could get some wake turbulence info on each aircraft you want in the shoot, then you can figure out the best way to arrange the aircraft in formation, to accommodate both the visual effect you're looking for and the wake turbulence safety issues.
If you're going to do a close formation for the photo op, then you'll need pilots with good formation flying skills, as crashes occur all too often with pilots (mostly GA pilots) who try formation flying, and don't have the special skills and training that safe formation flying requires. In fact, I think it would be good wisdom to confirm that each pilot participating in formation flying, has the necessary skills and training before you allow them (or encourage them) to participate.
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Safe flying to you...