Regarding the rear, do you have a tow hitch installed? The louvers you speak off sounds more like the cover/blank over the optional rear fog lamp which is installed on other markets of the X-Trail such as pictured. On the North American 2nd gen Rogue, a rear fog lamp is not installed and the louver takes its place.
(X-Trail and 2nd gen Rogue are very similar, unlike previous generations X-Trail and Rogue).
If you have a hitch, the receiver should extend past the bumper and you can tether your kayak to the hitch.
