When aging pizza dough in the refrigerator for 1-2 days, I mix the salt and "Saf-Instant Dry Baker's Yeast" (a Japanese brand) with the flour and add room-temperature or cold water. I always get lots of yeast bubbles within hours in the fridge, and lots of rise when par-baking, so I know the yeast is happy.
When I tried making same-day dough, I fell back to habits I learned as a kid, to mix the yeast with water as hot as I could stand my finger in. I mixed salt in that water too, and that was the only time in years of weekly baking I got no rise. Question part 1: Does salt kill the yeast??
Question part 2: Is there any reason to even use hot water if room-temp water works fine with this brand of yeast?
Question part 3: is there any reason not to simply use the mix of dry ingredients that I have success with with refrigerated doughs? If not, why do books/recipes/relatives insist on the hot water dissolve-the-yeast step, which means you have a couple more utensils to wash?