I see a lot of ppl wondering why they don't have business demand. Its because of the mixed use buildings. The instant you would get demand it will go in one of the mixed use buildings. You will get more demand eventually, I had the same problem in my city and then I realized I had many mixed buildings that still didn't have a company inside.
Maybe try using boulders instead of rocks for the waterbreakers... they're much larger, then you can add up some rocks to make it more uneven, and then some bushes in between... and piles of trash also blended... just sayin'... ;)
You uploaded this video yesterday but soon deleted it and if I'm correct it was because of the audio problem in the first 30 seconds of the video though the problem was there for very few seconds but the fact that you want your content to be perfect is just amazing!!!!.
13:43 you can tell when a service building has a designated zone by looking right above the select operating district button. For example: at 13:57 the game doesnt appear to have assigned the crematorium correctly because we do not see Sunnyside listed. Also i think your districts are probably too big considering youre trying to limit insane pathing. Then again i havent experimented enough with huge districts, so you might be right. I liked zoning stuff as a function of population, and i would zone an area that contains 1.500ish kids and 1.500ish teens (+/- 200), put a school complex in the middle, and call it a day. Haven't played the update yet, so the schools capacity might've changed and that might change how i limit my districts.