5 gallon water bottles are food grade and work great for fermenting. I use 5 gallon Kirkland bottles and 4 gallon Sam's club bottles. Only down side is they aren't big enough for a 5 gal batch, but I usually do 7 and 8 gallons and one of each is perfect. They don't break and if you want to...
Bittering hops are used to offset the sweetness of the malt. They have to be boiled to extract the alpha acids. Does the kit tell you the IBU's? The extract may have unfermentable sugars in it that the yeast will NEVER eat. I agree that a quality kit with separate hops and possibly steeping...
For bottles use soda bottles or get your friends to save 16oz BMC screw top cans. You will never go back to glass. Rinse and sanitize then fill and squeeze out the oxygen.