That depends on what setup you want to have. You can use this sensor to trigger another smart device (bulb, outlet, switch, for example) the other device does not have to be HUE but you will need another app or hub if it is not hue.

Yes.
"Make sure your Hue bulbs are connected and powered on, then head into the Alexa app (which you should have already installed when setting up your Echo). Select Devices, then the Plus button, then Add Device. After a few seconds of searching, your Hue lights should be detected and added.
If you prefer you can use a voice command instead: say "Alexa, find my devices" and your Alexa smart speaker will scan your house for compatible Hue bulbs.
However you add the Hue bulbs, once they're connected you can control them through the Alexa app or via your voice, with commands like "Alexa, turn the bedroom lights off".
Through the Alexa app you can group your Hue bulbs together and even group them with smart lights of a different brand. However, without the Hue Bridge you can't create custom scenes, have lights turn on or off based on your location, or access various other advanced features available in the Hue app." -the-ambient.com

if the bulbs are zigbee and can be added to the hue app then they will work with this. otherwise you might be able to use a 3rd party app to trigger an event using this sensor with your bulbs. (smartthings can do this)

Anytime I subwoofer has two inputs Left Channel and right Channel and you only have one output from your receiver you definitely want to check the manual on your subwoofer as it will definitely go over this. In most situations you would just use the Left Channel input on your sub.