Answer yes. it is $22.81 cents on Amazon. but i suggest you get a piece of Tyvek instead. lighter, cheaper.
Answer We do not currently carry a footprint for this tent.
Answer Yes, but as far as I can tell not from Sierra Trading Post. The Zenith and the Zephyr are essentially the same tent. Just different color schemes. You can buy a Zephyr 2 or Zephyr 3 footprint from numerous online retailers and it will fit your Zenith tent perfectly. Hope that helps!