Spotify handoff

So I’m very new to this and I’m kind of like a squirrel dashing from one shiny object to another but my main purpose in using the platform is for my house audio interface. I have a monoprice six-zone controller configured with a couple of sources. It works fine in the sense that I can turn zones on/off and select a source. I also have several Sonos devices that I was using before I purchased the controller. One of the devices connected to my MP controller is a Sonos so in theory I can group across both the zones it controls as well as the individual devices. I also have a couple chromecasts/google home devices that I use primarily to connect to bluetooth speakers but I also have a chromecast attached to my MP controller. It’s a lot and it’s kind of messy and I should probably decide on a standard but whatever.

What I’d like to do is create an automation where if I’m listening to Spotify on my phone either through my car’s BT or using headphones and I arrive home and my wife isn’t already home then have spotify handoff to home system. That handoff would be to turn on my living room zone, have that zone pick the Chromecast, and then have Spotify change the Spotify Connect to that Chromecast (or Sonos but I’ve had problems with Sonos, Connect, and the Spotify API in the past). I’d actually starting writing a HUD that would do part of this before I discovered HA/Hassio.

Is this possible? How would I go about doing it? I’ve spent the past couple of days playing with a lot of different features but this is my first attempt to do anything more than, “let’s see what this does.”

On the flipside if I wanted to continue down the path of my HUD project which has decent spotify integration and connect works, is there a way to send a command to HA to power on my zones and select a source. I’ve looked briefly at the RESTful API but it’s not super clear on how I’d do this. I’m a little underwhelmed by the UI in general and might be happier building my own UI and communicating with HA via API.

i had a similar use case and solved it by myself via nfc tags. automating it would also be possible but there just too many conditions to consider: what if my kid is in the house sleeping while i automatically let the music turn on in the living room with a loud volume? so i opted for touching my mobile phone on an almost invisible nfc tag sticked to the wall outside next to my door: