Android app decompile & modification

I have a chinese apk that has a game plugin (another apk). The game plugin overlays onto a popular game and adds some features (requires root btw). The only thing I need from the parent apk is the code that launches the plugin and the game. I need this code to run in a blank "hello world" app, so the new blank app acts as the new parent app. Note: The plugin app already runs by itself, but it does not connect to the game without the parent app, and the plugin functions crash. Part of this job is to ensure that the new blank app acting as the parent app is a viable replacement and the plugin works like normal. I am not familiar with smali, so I may have missed another dependency of the plugin, but as far as I can tell, the plugin has everything except the launch function that opens the game and attaches the plugin to the game.