This is an inter-app audio issue ,, I just bought the app AKAI Professional - iMPC app. The app does not show up as an inter-app audio device in DAW Multitrack ... In the App Store it boasts it's inter-app compatibility with iOS7 ... Does it really not work with iOS8? Dang! Is that the issue?

Sometimes this issue is caused by a install error. It's worth trying to reinstall the other app, and/or see if it shows up in another host (AudioShare works great as a sanity check). Also reboot the device to see if the IAA controller now picked up the app registration.