A very different hack indeed. A nice concept but as you say the storyline needs some developing for sure. For example, this "reward" seems as if it is going to be difficult to determine. As i've looked over what you've put on paper so far all i can forsee is a small shortlived hack as it doesn't seem as if it would have great life span. The other thing i'm sceptical is how you plan on having the action or how you're actually going to take the picture for example. Will you be using the "Safari Zone" battle script or be doing something different? Either way it seems good but i think if the entire hack is going to be just like catching pokemon in the safari but instead capturing images i can see that aspect of the game getting slightly bland and boring. Again i don't know what your intention is or whether you've developed one in detail.
Your spriting is very good and your inserting is very clean. You're using Unlz well too. The hack looks very nice and fresh and well layed out i just don't know how longlived the storyline can be. For this type of hack you are going to have so much space to work with. Side quests are definately going to be a key aspect to keep this going. For storylines and sort of different side quests and storylines, the Pokemon Ranger games are quite good. So try looking at the spin offs for ideas too. I would first suggest you develop the storyline, work on side quests then explain how the photo taking will work.
I do like your aspect and it is an ambitious idea. I wish you the best of look and i shall be keeping my eye on this and taking note of your updates.
Hooray for something different. ;]