Think you are right about the adapter… Apple store: Lightning to Camera Kit = £25. Lightning to USB = £15 (unsure if this works as it seems to be the camera kit that is specified for connecting to outboard). This will let you use your iPad4 with outboard gear that has a USB connection.
Also, as the Alesis iO is a unit where the iPad slides into a mount, I don’t think there is space to include a lightning to 30 pin adapter and still have everything fit as expected.
Stevo…