EDIT: This is wrong, see below.
The core creates the shrapnel and the core passes along its stats. If you were to cast Volcanic Orb and then begin to channel an ability, the shrapnel would not get any additional stats from you. The inverse is also true, if your stats go down after casting Volcanic Orb, the shrapnel are not affected by those stat changes. You could take off all your gear and both the orb and the shrapnel would be unaffected.
In short, once the Volcanic Orb is created, it and the shrapnel it creates completely ignore any stat changes which happen to you.