The liner and cargo tray are separate - and probably a bit of overkill. I like having both though because the liner keeps dog hair off the carpet bits. The cargo tray keeps things from moving around (somewhat) and liquids or dripping wet dog on the rubber. You can probably do either or if you didn't want both depending on your needs. What I didn't show is the liner comes with a bumper protector that velcros on - I keep it in the spare wheel area and have only used it when loading boulders/rocks into the trunk.
I have used Weathertech on multiple cars and really like their product. They have something similar to the one Mazda makes but it is plastic instead. Easy to clean and super durable. I am actually about to order one. They sell it with or without the bumper protector. Im getting the floor liners as well.
http://www.weathertech.com/mazda/2015/cx-5/cargo-liner/
But it doesn't cover the seat back or the side pockets.
There is a hard tray for the CX-5 that is available thru Japanparts.com that is similar to the hard tray (rubber) that we have but it has pieces that cover the rear of the seat backs as well. That might be something to look into.
I'm considering picking up the rubber tray from mazda as well as I recently learned that if anything spills in the little side pockets it runs down into the spare wheel area. I had a milk jug that leaked and filled my spare wheel well on me. Does anyone know if a standard Gallon jug fits into the side pockets of the rubber tray?