Help with Core Audio Interfaces

I have a CONCERT set up for a practice rig.  One audio channel for guitar using an IK iRig HD.  One audio channel for an iPad using iConnectMIDI2+ and it's audio pass thru feature.  One Instrument Channel using a Piano sound.  I made an aggregate device with the iRig HD and the iConnect.  Also the iPad and Piano SET at set level so I can change through different guitar PATCHES for clean, distortion etc.  The Piano uses an MPK Mini for control.

iConnect, MPK and USB drive are using a USB 2.0 hub.  The iRig is connected into the MacBook USB port. (would like to use the hub but doesn't seem to consistently recognize the iRig.

Inputs 1+2 are iRig and 3+4 are the iConnect.  Output is 1+2.  When I open the concert the aggregate audio device is set in pref's.  But the iConnect (iPad) is the only input recognized and now plays audio on input 1+2.  The iRig isn't recognized at all.  After some changing the audio device and the going back it seems to finally see the iRig and the iConnect both and everything works as designed.  This is being done on the MacBook Air listed in my sig.

Any idea what is going on?  Help and thoughts are appreciated

Pauly