In Israel we have cheapo chinese rear camera installed by Honda reseller
in place of camera you have plastic case (camera have round body with metal latches) - the camera placend in this case (they not removing that case but drilling it, then they doo hole in rear door body to install camera cable and when finished they use silicone glue to seal this hole, the camera power + (red wire) connected throught fuse to reverse lamp, then coax cable from camera run throught rear door with other wires to infotaiment
In my case this is Honda Connect so connection should be easy (not opened so i can't tell exactly how they connected to it) but on japanese market i seen adapter for rear camera from hondas 8 pin connector to RCA.