The main concern you will encounter when merging two manifests will be the multiple activity problem, : Basically, whenever 2 manifest both contain a MAIN activity (identified in the manifest as : “android.intent.action.MAIN”), you will need to have one of the activity “inherit” from the other.
Here’s a link that might help you get started on that.
Also, I recommend looking into their respective documentation, I’m sure one of the two actually tells you how to extend their plugin.