App developer needed to build app for both Android and iOS, app will control bluetooth device

This project is for the development of a new app for both android and iOS. We are a new company that is developing an electronic devices for a specialty niche. The devices will be controlled via bluetooth through our customer's phones. Our first prototypes, including custom PCB boards and firmware, will be available in about a month (if nothing goes wrong!). We are looking for someone who can help us develop the apps to run these programs. In order to simplify the process and reduce our cost, we've thought carefully through the functionality and look of the app. We don't anticipate having multiple phases of trial-and-error to decide how the app should work, though once it gets into the hands of consumers we will get feedback and correct anything that isn't working for them. The design and requirements are simple, so hopefully there won't be too much difficulty in this area. The app will: -connect to bluetooth headphones and play music and standard tones with stereo music effects -connect to two custom bluetooth devices with haptic motors with preprogrammed settings -store custom settings What you will be provided with: -drawings of exactly how the app should look and operate -graphic design elements -firmware for operating the custom device What type of freelancer am I looking for? -someone with experience with building new android apps, iOS apps, and working with bluetooth devices -Ideally we would find someone we can work with in the future as well for future maintenance of the app and new features that may be added. At a later time, we will add another bluetooth device and may consider features such as as profile storage and possibly remote operation of devices through the internet This is the first time I've done a project like this, so you tell me how long it will take and what it will cost.