Hi Lockeye, welcome to the Forum.
I really don't think there's anything in that lot which would be too hard for a basically competent driver in a 2WD with reasonable ground clearance given relatively good weather, especially if it's travelling in company in a 4WD with std recovery gear on hand. It'd probably be a good idea to make sure the 2WD Navara has rated Recovery Hooks up front so you can hook up a load equalising bridle to give it a hand if required; & the same at the rear, or at least a good tow hitch with a removable ball & tongue assembly (cos you simply never
recover off a towball!) but you can slip a tow or snatch strap into a 50mm reciever & use the high tensile pin thru the eye to secure it there, knowing the tow hitch should be well braced & secured with HT bolts spreading the load across the rear chassis &/or sub-frame.
But regardless, given a well maintained vehicle, some reasonable driving, good weather, & a bit of care, you really shouldn't have any hassles! Remember, most of those roads were opened up by 2WD vehicles... sure, they might've done it a whole lot tougher back then, and there's no denying that it is
going to be a little harder on the vehicle, plus it will be a lot harder if not impossible if things get greasy or wet, but you certainly won't be the first to do it and you aren't likely to be the last to take a 2WD out there either.
Now, all that said, while it's well worth ducking in on the Cordillo road to visit Cordillo Downs & the biiiig shearing shed there, I'd strongly suggest that you return back the 40 odd km to Arrabury where you turned in & then continue on heading North on that road up to the Birdsville Developmental Road (fm Windorah) & follow it into Birdsville past Betoota (locality & pub ruins) simply for the more enjoyable scenery & safer driving.... even if it's not necessarily anything much 'easier' & it is a bit longer, you'll still probably get into Birdsville quicker. Once you pass Cordillo, unless it's recently been graded between Caldelga & Cordillo Downs (& sometimes even when it has!) the Cordillo Road is usually a real pig that's just not all that great for ANYTHING
driving on it, especially if you also hafta contend with the road trains that frequently use it (altho they usually only use it going out
cos it's often too hard on the livestock when they are heading back East or South!) but that does mean you could get stuck behind one... or more! That's really not fun any time or travelling in either direction, but it's definitely WAAAaaaaay less fun on a narrow track where it's pretty much impossible to pass them while moving in either direction & the dust & gibbers they throw up can destroy your car in moments - and the track is generally rutted & corrugated & covered in loose scree & sharply fractured gibbers & is extremely unkind to tyres, vehicles, & occupants alike!! Not only is it easier & safer on the tyres, vehicles, & the occupants to take the other road via Betoota, but the scenery is better that way too, if you travel at the right time affter rain you stand a good chance of seeing hillsides covered with Sturt Desert Pea & other Desert Wildflowers, the road is more open allowing for easier travelling so you can enjoy it a helluva lot more, plus you'll have more chance of making Birdsville with both vehicles, all their tyres, & all the occupants still in one piece! I've seen the Cordillo Road rattle bull bars off more than one vehicle, and I can tell you the damage caused in the resulting 'accident' when your bull bar drops onto the road in front of you while you're travelling at any speed is just not nice!!
So take your time, take the scenic route, and enjoy your trip!