Ugh, labeling is a complete waste of time with a cat around. Those boxes are just giant dominoes waiting to fall. Your cat is absolutely planning its move right now, probably eyeing the weak spot. My old cat would chew the labels off for fun, then push the whole stack at 3 AM. You're just setting yourself up for a bigger mess later.
3M label adhesive actually makes a decent cat deterrent if you press them on firm enough. Gives your collection a fighting chance against the midnight demolition crew.