Find and hire candidates with this very specific skillset (we tried to hire for this role for over a year with no success)
Really? You weren't able to fill this role? I can almost guarantee that you could throw an extra 25-50k at someone competent to fill it.
In the end we no longer share mobile code via C++ (or any other non-standard way) and instead write code in the platform native languages.
I've started to comment on this across the interwebs. If you are a cross-platform (native) mobile developer, and haven't taken a look at Xamarin, you _need_ to give it some attention. Xamarin.Native specifically is the best solution I've come across that mostly gets out of your way, and has robust library ecosystems and sane interop.