the tires are key
my main off-road rigs are both fully rigid, but with fat, knobby tires, typically run towards the lower end of the recommended PSI range. A CF headset would be a bad idea. and, FWIW, suspension forks are tougher to run full coverage fenders and front racks on. plus, touring in serious "ATB" conditions with racks and bags often leads to difficulty with bumps in the trail, hence the popularity of one-wheeled trailers with off-road tourists.
If you want to make that hybrid as trail-worthy as possible, buy the fattest, knobbiest, ugliest tires that will fit between the stays and brakes. Keep in mind that onroad performance will suffer, so keep the slicks handy for rides with more road aspects.