Hi Dan,

  I may not entirely understand your app’s functioning, especially the “device” portion.  However, have you looked at hybrid app libraries such as Ionic, or Cordova? They also have plugins that deal with audio via the HTML5 standard which may be all you need. There are also Cordova plugins for Bluetooth serial communication. 

  A few years ago I created a Cordova Pd plugin that I never ended up using because the project got canceled but I’d be happy to share it with you if you plan to go in the Cordova direction.  

  But in my opinion as someone who has used Cordova/Ionic as well as Android API and iOS API to build apps, using the native languages to each respective device has always been more reliable, easier to debug and faster performance than Ionic or Cordova when dealing with audio, especially libpd.  Java/Obj-C/Swift are not terribly difficult to learn if you are familiar with another programming language.

 My two cents.  

Good luck. 

-Rob