You are correct on the prop. That is all it means. 10 in diameter and if it could drill into wood it would move 8 in. forward with one turn. I am not sure if that's what you meant by 8 in. pitch but, that is the way its labeled.

As for as the batteries, usually the amps is what you setup draws. i.e. size motor, prop, and maybe gear drive. The 1500 mah can be thought of as the gas tank. That's how much power it holds. The bigger the number, the more 'gas'. That number will not change power, only length of time of usage with a full battery. The amps are how much 'gas' your setup uses at a set period of time, say a little car gets 30 mpg and a large car getting 15 mpg. High discharge means you can have a setup that pulls a lot of amps and be able to get it from the battery. However, the more amps pulled, the less time in flight. An example it the speed 400 motor with direct drive and a properly matched prop will PULL about 10 amps or so. A speed 180 motor with or without gear drive pulls between 3 and 5 amps, I think. Others know a lot more about that part.

Hope that helps.