I'm finding it very hard to follow the logic through your code.
It seems that a ping interrupt calls echoCheck() - is that part working?
I can't see where oneSensorCycle() is called.
I don't understand your description of the problem. In each iteration of loop() you seem to be reading 6 sonar sensors in a FOR loop and the 6 analog pins without using a FOR loop. It also seems that the sonar sensor will only be read when some time has elapsed but the analog pins are read every time.
Perhaps it would help to post a sample of the output. I don't have a sonar device so I can't try your code.
...R