Of course you're limited to the INT0/1 pins then.
So PCINT is just not implemented in MySensors? Code is probably based on an old datahseet:
Because that's just wrong...Looking at hwSleep for AVR it looks like it's just using attachInterrupt with the passed through mode. I'll test later because in fact I'm working on a project with a MPR121 touch controller that wakes up my Pro Mini on FALLING so I change it to CHANGE and see what happens...
Anyhow, @kk02067 I'd use INT0/1 pins if you can...also, just measure the current consumption und unplug the nrf to see how much it changes. My mentioned MPR121 project consumes about 0.5-0.9mA in sleep and ~18mA in awake (MPR121+Pro Mini+nrf) just to give you some ballpark numbers. Consumption went to 5mA with nrf unplugged.