Yes, I've consider not carrying both phones so I just need to weigh which one is less ounces. They weigh more than you think. Obviously the camera and Spot stays. The GPS I don't take everytime. Its more for when I'm waterfall hunting and have to leave the trail.

As far as water it depends on how much water I expect at the location. For a normal trip where I know there are some reliable sources here and there on the trail I carry a 2 liter bladder pack with a 16oz bottle. I use the bottle for mixing up with the iodine and the bladder I just drink while hiking(its normally empty at the end). If I'm going somewhere without water obviously that weight goes up. Though if I'm going to a trail that say follows a lake I'll just take the 16oz bottle.

I used a tyvek tarp for a while but went for the poncho instead since I'm already carrying it. Its cheap enough if I tear it up being a groundcloth I can buy a new one. Plus its a lot cheaper than replacing the tent.