Scope app development

I have an idea for a share-trading related app I'd like to develop that is linked to other initiatives I am pursuing. However, I've never created an app before. Before developing the app, I need assistance to scope out the project. I'm looking for someone with experience in all aspects of developing apps, who can provide me options and recommendations in relation to things such as: > app design (I have a starting point in a powerpoint deck but it needs work) > pricing (there are a number of features I could offer as a premium service) > advertising (I'm interested in limited and very targeted advertising) > data sourcing (I need to get access to various stock market related data from different markets) > platform (apple v google) > publication & marketing > other important things I probably haven't thought of yet I'd be looking for estimates of costs, comparisons with the approaches others have taken, revenue opportunities, etc. I'll provide more detail to the winning applicant. Previous experience with share trading apps would be ideal, but perhaps not necessary. I don't have a specific budget, but will pay an hourly rate and am happy to see where the work takes us. I'm open to suggestions on rate and approach, so please give me an overview of what you would propose in your response.