The star ratchet hubs are just a solid design, winter use is just an added bonus, I'd say they'd be worth it but that's just me. The mavic ID360 stuff is supposed to be good but I haven't seen them first hand yet, older ones were more of a pain to rebuild though. But if you're leaning mavic I wouldn't not recommend them or anything.
The graphics are just stickers btw, hair dryer and a couple minutes of your time and you'll have a sexy all black rim
As far as hydraulic brakes in cold weather, they're definitely affected (they don't freeze but they'll get sluggish and pump up a ton, especially if they haven't been bled for a while and there's any water in your lines) probably starting around -15 but only if you're storing or locking your bike up outside for decent amounts of time. The ride itself won't be near enough to affect them as the heat from braking usually keeps em at a decent temp if they start at room temp. I have hydraulics on mine and I'm tempted to switch back to mechanicals next winter cuz my bike's locked outside a lot of the time.