Changing horses: adding midi to an effect plugin

I've got a plugin I developed as an audio effect, but now want to add MIDI triggering to it so it functions as an instrument.  However I still  want to have audio input as an option. What are my choices?   I've started doing some manual tweaks

I've changed this: 

 #define JucePlugin_WantsMidiInput         1

Written some MIDI code in the processBlock

Found this, which will help with the resources file and the AppConfig.h

                kAudioUnitType_Output                                   = 'auou',
                kAudioUnitType_MusicDevice                              = 'aumu',
                kAudioUnitType_MusicEffect                              = 'aumf',
                kAudioUnitType_FormatConverter                  = 'aufc',       
                kAudioUnitType_Effect                                   = 'aufx',       
                kAudioUnitType_Mixer                                    = 'aumx',
                kAudioUnitType_Panner                                   = 'aupn',
                kAudioUnitType_OfflineEffect                    = 'auol',
                kAudioUnitType_Generator                                = 'augn',

I guess I'm going to have to go for: 

        @constant               kAudioUnitType_MusicDevice
                                        Used to describe software musical instruments such as samplers and 
                                        synthesisers. They respond to MIDI and create notes, which are then controlled
                                        through parameters or MIDI control messages. See <AudioUnit/MusicDevice.h>

And then have an audio effect version of the plugin as a separate binary. 

Is there anything else I need to change? 

I'm starting to think I should have been doing this using the introjucer ... but I'm nervous that as I've been ignoring the thing since i got started it'll lose my custom build settings in xcode ... or maybe it won't :)   If I've added a billion source files, all carefully laid out in IJ and then set up some custom settings do they all get overwritten if I go back to the introjucer for a bit of a reconfiguration?

cheers! J.