Hi,
I have read the project description and I see that you want to build a cross platform app in xamarin as we have expertise in the platform with xamarin forms as well as native app on xamarin so I am eager to work with you on this project if given a chance. I have been a freelance windows, web & mobile developer for 10+ years.
As you mentioned in the document You have already exposed and rest based service to search stolen objects. So UI will be common for both ios and android and we will use resource files to support localisation. In case of internet is not available we can also maintain some local database and sync when online. We can discuss more about this.
Our team already working with VS 2015 for Universal apps, xamarin and other window based apps. So it will be quite good for us to work on this project.
I have done extensive work using .Net, C#, WPF, WCF, MVC, Xamarin, PHP, MySQL, Wordpress, Ajax, HTML, CSS etc during this period and I can handle any platform with full command.
Please let me know if you have any queries regarding my proposal and I will be happy to answer them.