The AirPods scripts, right now, is in two locations. In a future version I will merge them, I'm also planning on allowing you to customize your AirPods' name in the settings window. Keep an eye on the experimental versions! Until then, here are the two widget locations:
First one is in the menu bar.
Second one is in Connectivity Actions.
Inside the script, edit the highlighted bit to the name of your AirPods:
For Spark: Make sure you have dock badges turned on - they must be turned on separately inside the app's preferences (see below). Dock badge widgets do actually check the dock icon for a badge, which is how they work
For Twitch and Facebook: Yup, as you guessed, they actually do check for a dock icon! For Facebook, I recommend making a web wrapper app with Fluid (http://fluidapp.com). It comes with built-in support for Facebook notification badges, too. For Twitch, they have a native app for Mac, so you can download that
Hopefully that helps! Cheers