yes, these both solutions are quite good, especially paragon dropouts if manufactured to a high standard. if not, i can see an additional point of failure and source of creaks. rear dropouts is a high load area and those little bolts should better be strong enough.
surly tensioner looks more reliable, as there is little to go wrong but it looks a bit out of place on a bike which was designed for single speed or hub gear use from the start. it's not an elegant solution for an elegant new bike, in my view.
fixing flat tyre on genesis day1 would be a bit of a chore (loosen both axle nuts, unscrew tension nuts, take the chain off the chainring, loosen rear part of mudguard stays to slide the wheel out, fix the flat, do everything in reverse, re-adjust and tighten properly). i'd probably trim the mudguard to the minimum so the wheel can slide out easier. or install marathon +, tyre liner and slime inner tube on the rear wheel
