Home automation and Multiple rabbit holes

I've got two problems I'd like to solve, both of which seem easy, but don't have a ready-made bolt-on solution.  It feels like I'm missing an a-ha moment that would tie it all together.

Scenario 1:

Aranet4 air monitor doing CO2 monitoring

The Aranet only supports bluetooth, and doesn't have a web-hook or central logging system.

Winix Smart wi-fi 

Have it paired, and it supports alexa

Solution:

Buy/deploy a raspberry Pi with Bluetooth.  have it pair with the Aranet when the aranet is around.

Constantly read the Aranet.

When reading > 1000, then send a hook to Winix (via alexa?) to turn on

When reading > 900, send a hook to winix to turn off

--

Wemo light switches

we have switched outlets, which we're using to control both a fan and a light. Frequently turn off the light via the switch when the fan is supposed to be on, which kills both.

Solution:  look and see if I have hot wires in the wall and could make it half on?  
or:  Put in two wemos.  Now integrae them to homekit.  

Need:  Find a switch that will take wall power, and then just send a notification to homekit to turn certain devices on and off! Wall mount that so now wlal switch drives homekit, not power.