1. yes! i climbed Low Mountain in the pouring rain and stayed bone dry! there are 6 other crags that are listed as "dry" crags, and 4 more that have some dry routes. the guide conveniently breaks every crag down by sun/shade (morning, afternoon, and evening), climbable in the rain or not, and number of routes in each grade. august is typical rainy season, and is also very hot and humid. ask ricky or read the latest Climbing article for a 1st hand account on august conditions.
2. not me
3. my estimates are based on high (or dry) season in october...
$5-$15/night lodging, $7-$20/day food, $4/day crag transport (cheaper to rent bicycle). this may be more or less...depending on what you can deal, and how much deprivation you choose.
Electrolytes...it's what plants crave!