1) Just rinse with water,
2) Hold the disc in the tongs and light with a BIC lighter or similar. When it starts flaring up set it on the coal/ash tray on the hookah and wait until its fully heated to use. Don't break them in half unless your using the big 40mm on a larger bowl. I use one disc, whole, on my small Lebanese bowl.
3)foil, never noticed a heat diff by side. Use one layer of HD foil, two layers if your experiencing overheating issues.
4)Do not clean the hose after use unless it's a washable hose. The hookah you can rinse out and every two to three uses give it a cleaing using baking sode and water. Or the beer method shown in this vid from Sambooka.
5)Ziplocs are fine, do not refrigerate. You can store it in any cabinet. Some tobacco needs to be stored in darker locations. Stir before using to mix the juices in. Remove any stems that may cause issues. Pack loosely and below the foil level. And enjoy!