BigDave was correct to caution that trichlor and bleach should NEVER come into direct contact with each other; bad things happen if they do!!

+ If you've got 15+ pounds of trichlor on hand, why do you need more right now? Use them in the floater if you have one.
+ Use the bleach you have same as 8% store bleach -- actually because the store bleach is probably fresher, it may be stronger, so use up the Kem-Tek first.
+ You probably won't need the acid for now. Be careful how you store it; tiny leaks can release enough fumes (hydrogen chloride gas) to cause SERIOUS corrosion to wiring, tools and equipment if you store the acid in a garage or other enclosure. Bagging in a garbage bag is always good. BUT . . . the 1/2 strength acid you have fumes MUCH less than full strength (31%) acid.

As far as future purchase, you probably need some borax to keep your pH up, while using the tabs: Walmart is good. Given your test results on the tap water, you really don't need to use washing soda (soda ash, pH Up) or baking soda (bicarb, Alk Up) since both increase your carbonate alkalinity.

I haven't seen undiluted Pool Time trichlor in several years, but if it's available to you, that's fine. The best prices I know of, for most of the country, are the Pool Brand dichlor (50#) or trichlor (40#) sold by Sams Club in many areas. The last time I checked, Costco was selling only diluted products, that should be avoided.