Don't get side tracked by our chat on Serial your answer to a CNCv is in my view perfectly acceptable althoughmight suggest another option rather than individual pin interrupts.
Whats the rate of change you are looking at ? i.e. what timing could you accommodate between hitting switch and motor turning off?
Before I took up training/consultancy etc., I designed industrial control rairly did we try and interrupt monitor all inputs in fact only the emergency stop.
Rather we read the inputs using a time tick interrupt, meant we could debounce the limit switchs as well at a known rate.
Have got back in, so if you want to message me with an email will send you a lump of code for
a. setting up timer interrupt and read and debounce inputs.
Your main loop can then monitor this and action as required..