Hi, my name is Valeriu, I'm a iOS and Unity3D developer, I work in mobile department of a software company from Romania. I work also as a freelancer for mobile projects, especially games. For you project I recommend you to develop the game using a game engine like Unity3D, Unreal or other game engine from the market. If you have all graphical assets already done, the process of creation will be significantly shorter. Otherwise, I can help you with modelling 3D objects/2D images that will be used in the game. As a freelancer I work also with 2 designers and they can help you with all graphical stuff and animations.
Developing a game with Unity3D will give you a cross-platform code that can be run on multiple device platforms such as iPhone, Android, Windows Phone. I got that you want the game only for iPhone but if the game will get popular you can at any time with minimal changes to make also Android version and post it on the Play Store.
Publishing a game on the App Store for iPhone requires an Developer account, it cost 100$ so if you would like to post the game to the App Store you will need to create an account with your name.
Regarding to your project I have the experience that is needed to implement the project and also I can help you with publishing the game.
If I got your attention please fell free to contact me for further information.
Regards,
Valeriu Popa