You may be able to experiment with a USB hub and Camera Connection Kit but iRig Keys was not made as a standard 5-pin MIDI controller (just like many USB controllers no longer have 5-pin MIDI connectors). It was also created long before Apple decided to drop the headphone jack from their devices so currently a better option may be something like
iRig Keys I/O.[/quote]
But that just doubles up on the iRig Pro i/o out I have just bought!
I tried with the USB adapter, and although it does work, however, I still cannot plug in headphones as that leaves me a lightning connector. I user Beyerdynamic pro headphones.
Sorry, Peter, but I have just wasted a couple of hundred pounds, and I am not pleased.
I have been a professional composer and sound man in the industry for 40 years. I don't like throwing money away.