Even if your ISRs detect the button pushes, all they do is update the ‘buttonPushCounter’ and ‘buttonPushCounter2’ state variables (pretty poor names to say the least). So, once you un-comment and start running the LED functions (rainbowCycle, etc) the program is still not going to seem very responsive. Each of those function will still run to completion and the change to the ‘buttonPushCounter’ variables (from the ISRs) will only take effect when it finishes.
That will still be a rather poor user experience. The right way to do it is to unravel the blocking loops in the LED functions and make them state machines.