A good set of snow tires and common sense and you will be fine. My current vehicle is a G37 coupe RWD and I've driven through snow and ice covered roads without issue. The only issue would be clearance
I would expect information to be out this year. As for kinks I wouldn't worry to much about first year. The platform is an upgraded version of the previous great chassis and the engine has been in the Infiniti line for many years. They have had time to work out the issues and learned.
The fact that they didn't do any close ups of the grey one make me think that is the production model. They wouldn't make another proto in a different color. Pretty sure the grey one is the production version.
They said that this is 98% production and I think that the grill is the part that can change. Maybe they wanted to gauge it before going into production. It won't take much to make the cutout less jaring.