What you were trying to do is not currently supported in UE4. You cannot make UE4 wire up keyboard for player 1 but first game controller for player 2 without modifying the engine. So basically it’s nothing to do with my plug-in. You have to find a solution to do that first and then I can help you with remaining issues you have specific to the plug-in.
There is something called *ControllerId *in the engine and it determines which game controller a local player uses. You can wire up the second controller for player 1 and the first controller for player 2 by setting *ControllerId *but keyboard is always bound to the local player with *ControllerId *of zero. Besides, this functionality is not available in Blueprint.