I feel like the instructions somewhere explicitly say not to do that, but I can't find it now. Either way, I would highly recommend not doing that.

The water doesn't go directly from tank to pot, it goes down, over, and up, through the entire machine, so when you're done, there's going to be residual water throughout the machine. If this were milk, it would all spoil and gunk everything up, so at the very least you'd have to run a cleaning cycle or two immediately after every time you make hot chocolate this way.

I'd pick a much cheaper, easier to clean device, like an electric kettle. I don't know if these are designed for milk specifically, but if you were going to try it, these would be much easier to clean afterward.

This device can plug into speakers using a stereo plug or RCA cable. You can google image to see what those plugs look like. To connect your laptop using this device, the setup would be something like this:

Bluetooth compatible laptop (assuming yours is) -----> Logitech blue tooth receiver -----> RCA cable or stereo cable ----> speakers.

But honestly, if your only need is to connect a laptop, and you don't need to connect via bluetooth, you'd be better off buying a cable that plugs directly into your speakers. If your speakers have a stereo or RCA input, you can buy cables that go directly from your laptop to your speakers. If your speakers don't have those inputs, this device won't help you anyway.

Good luck!