It sounds like you've been reading Barry's book! Good for you! Everything you need is in there. It looks like you just need one TIU plus a spare. DCS locos want fixed outputs (from the TIU) and conventional wants variable. You have two of each on your lone TIU. I am nobody's version of an expert on the right way to block a layout. But don't be shocked if, when you start to block it out, you start to think about a second TIU. It is not necessary.....and yet....I'd be tempted.
AIU's....hmmmmm...this is a small layout within easy reach for most stuff. I'd consider using some ground throws for those yard switches instead of AIU ports. But that's just a preference. Wifi is good. I prefer the remote control but since they are no longer made, that is problematic.
I like the Z-4000 and I don't think you can go wrong there. I started with Z-4000s and switched to Lionel 180W bricks because I made a commitment to run only DCS or TMCC locos---I gave up conventional and I have never missed it. Your ZW is about the equivalent of one 180W brick. I LOVE those handles! But my lone ZW just runs accessories and switches for old time's sake. I don't run trains with it. I like separate power supplies for everything--switches, scenic lights, signals--all separate. But economically speaking, some of these could surely be combiined.
I love DCS. I bet you will too.
Best of luck and PS--I really like your track plan too.
Don
