Your idea is not bad, but why not expand it some more.....I jumped outa airplanes for almost half of my 9+ years on active duty in the Army, and you wouldn't believe the amount of crap we strapped to ourselves, and to our parachute harnesses....of course, those parachute harnesses were designed/configured with appropriately placed, heavy-duty D-rings for attaching things (like your reserve parachute, 70+lb rucksack, weapons container, etc, etc).
The point I'm making is not to throw that much crap onto your parachute harness, but to expand your current configuration. What about something smaller, with sturdy grab-straps or D-rings, that you could still grab-n-clip to your harness.....something like maybe the size of the old style butt-packs. Something that small could be ridden-in because of its light weight, unlike the stuff I jumped in the Army, which we lowered below us on a lowering line before hitting the ground. Also take a look at the Eagle Industries E&E bag. I just bought one, and am really liking it. It has carry handles, stowable backpack straps, and a side-release buckle hang-strap. The interior has, depending on the size you get, either four or five interior mesh zipper-closed pouches, as well as a pouch sized to hold a 50 or 70 oz water bladder. I'm sure your ALSE folks could help you configure something that won't fall off of you with any free-fall/opening shock, would survive the impact of you and the equipment hitting the ground, as well as provide items to stock whatever it is you get.
The other point I'm suggesting is its far better to have a few important things like small amounts of food and water ALREADY on/with you, instead of being behind the power curve and having to forage for food and water. What if you are unable to move around once on the ground due to injury and/or hostile forces in the area near where you land???? At least then you can hide and survive a little while before having to obtain/create food and water.