You are a wealth of knowledge Thrall and it is appreciated.
Our soil composition is mostly clay and we have water issues to speak of. I do plan to slope the grade away from the house naturally and cut in a slight swayle to catch any possible water that could come off the property bordering mine in the event of a huge storm (just never know with today's weather patterns). The waterproofing we went with has a 30 year warranty, now granted if an issue were to arise I am certain they would find every reason imaginable to deny the claim.
In terms of the garage fill, the clay would work great if I could get in there to compact it in levels but the risk of blowing out the walls is too great and the majority of the fill will be needed against the walls. I would try and fill the center area with clay and tamp it but by the time I do that I might as well spend the money on a little extra fill. We are looking at recycled vs. sand to see what would work better in terms of both time and money. With the sand I can have it slung in while the excavator supports the outside of the walls whereas with the recycled I have to have the excavator pick it and drop it inside then fill the outside and back and forth.....in other words what I may save on material I may spend in operator time, negating any savings.