SUL Backpacking

Can I "do" Super Ultralight Backpacking, with a base weight of under 5 pounds (not counting food, fuel or water)?  Not that I need to go lower than the 9 pound base weight where I am now, but it could be interesting.  With what I can find online today, let me look...

REI Flash 22 Day Pack

I could take the 16 ounce REI Flash 22 daypack, which I am looking to buy for hiking and travel.  It has side and top pockets which will help greatly with organization and with carrying water, but would still be reasonably light in weight.  It is also on a special sale this week.
I can stuff my Thermarest Alpine down quilt into it, add my Sawyer water filtration (3 ounces) personal hygene, spares & first aid kits and a rescue blanket for the ground.  I won't cook on this trip so I won't carry my stove or pot.
Food would just be a snack (I would eat dinner on the way to the trailhead) and carry 2 breakfast bars for breakfast.
I would pack my raincoat inside the pack but outside of the waterproofing bag.  The Z-pad would be placed outside under the home-made stretchy webbing I would add to the front backpack ladder.  My Gatorade water bottles would ride in the side pockets.

SOL Escape Bivy (breathable)

What I would need for minimalist shelter is a SOL Escape Bivy sack.  At 8.1 ounces, the SOL will work just fine.  It breathes, so I won't soak my down quilt.  I'll add a low price head net to keep the bugs off my face.  Both will fit into the pack, inside the water-proofing trash compactor bag.
Maybe an ultralight tarp & stakes would be good protection in rainy weather, but I am not adding them here because they would weigh too much. I will carry a black plastic trash bag though, which I could rig up with my hiking pole and some sticks to protect my head if it did rain.
I don't carry a change of clothes, but would carry long underwear, a hat and sleeping socks for comfortable sleeping.
It all fits(!) and would weigh just an ounce or two under 5 pounds.  By adding the tarp & stakes it would be closer to 6 pounds.
Now, ready for a SUL-S24 (sub-24 hour) hike?