I've had sets of winter tyres for winter use back to 2000 - since before most folks have ever heard of them! I used to have to order from Germany.
I've learnt over the years that the key to a good winter tyre is the size, depth and spacing of the blocks at the shoulder (outer edge) of the tyre. These tyres are mediocre-to-probably-OK, as they are, for winter use. The differences between a good summer tyre with good shoulder blocks and a poor winter tyre with a shallow pattern is quite small and often less than the effort of looking for a specifically mountain-marked tyre is worth. In this case, I think I will see how these tyres fare first, before deciding if winter tyres are a necessary replacement for them.
So I won't be running winter tyres this year because a) it's a PCP car and I may well not be its owner for more than one full winter, b) it's a pig awkward size to buy good winter tyres for (let alone 'low rolling resistance'), and c) I don't know if these tyres particularly need changing for winter yet.
I reckon it will make very very little noticeable difference between running 'low resistance' tyres and 'regular' tyres in winter months. The additional demands on the energy will mean any tyre differences will pale into insignificance.
..and besides, if the weather is that cold, I will probably be wanting to drive one of my ICE cars just to keep warm (!), one has all season tyres on the other M&S already.
If I do keep the car and if I find that these tyres aren't good for winter, I would either ask Renault if they'd have any issues with me running 195/65/15 steel rims and tyres on the car (it is a standard size for the standard Fluence, and I can't seen any reason for interference with the brakes for the smaller diameter) or if they object I would simply find a tyre in the right size to replace the existing tyre, and one that I feel would be good in winter (if not an all-season). If there is a loss of mileage, then sobeit. Better that, than crash in winter. I don't believe there is all that much to be gained between a, specifically, 'low resistance tyre' and a 'regular' tyre for rolling resistance once above 175 x-section or so.
Personally, I find the tyres a little noisy. They ring and hum at certain speeds, on top of a usual road-noise continuum. (That being said, sometimes it is difficult to tell motor noises from tyre noises.) The pressures are quite high, as typical for low RR, I think it was 38 to front and 44 to rear. You should check the pressures routinely for the first few weeks to check the tyres do not have any slow leaks, so you should, really, have checked these already. I have tried running these even higher, to see if there was any fuel economy to be gained, and found none. Some additional road noise though, so I returned them to the recommended pressures.
You'll note that there is very little tyre deflection around the contact patch, so I'm happy there is probably nothing to be gained in running higher pressures. The car is very close to 50:50 weight distribution, front-back (usually being front-heavy for FWD cars).
Grip in the dry is surprising, especially with the vehicle stability controls. You can really boot it around a roundabout and let the computers keep the car on the road. I've only done it the once with any real gusto, but it was very impressive that there was no under-steer, given the enormous torque on tap to the front wheels that the computers have to keep under control. Not had too much experience of it in the wet, yet.