+ If you can find "sodium dichloro-isocyanurate" or a product with a similar active ingredient (= contains "-dichlor-"), NO other active ingredients, and an active chlorine % of 55% or higher . . . that should be OK.

+ You live where it's cool, but still I wouldn't get more than 25 gallons of 6% household bleach. Check the %. Better to get a 6% store brand, than Clorox, unless you are VERY careful to get PLAIN Clorox Ultra.

+ I can't imagine you'd need more than 10 boxes (47 lbs) of borax, but borax WILL keep, so if you get too much, you can use it in later years. The only exception would be if you want to do the borates > 50 ppm treatment, but I'd recommend saving that till next year, when you have more experience . . . UNLESS you are planning to leave most of the water in your pool. (I'm assuming you're planning the AG weatherization common in the US North East -- draining 2/3 of your pool water.