You forgot a big part of Alexa that could be helpful. The echo can control home automation, meaning with a smart switch you could just say, Alexa turn on my water pump.
For Sale 15 Gallon Mash Tun with False Bottom, Sight Glass and Blichmann Auto Sparge (Lima, OH)
The false bottom is a tight fit, and doesn't sit flat. This MT has served me well but I upgraded to a Blichmann pot. Included is a ½" SS Ball Valve, Sight Glass with calibration marks, Blichmann...
My 1.5 Triclover element cover is being delivered today. I called a local weld shop about estimated cost for welding the triclover on my pot and they guy said $50. :(
maybe I should have gone the silver solder option.
If you get the right fan it should work. I bought a 6" inline fan off eBay for ~$75 shipped and built my hood out of wood for about $30. I don't see why this idea wouldn't work.