The Q12 is very loud for a small speaker and can fill the sound of a room of 80-100 sqm.

You need to purchase a micro USB cord.

Yes, it works great with Alexa.

It is IPX6 waterproof.

It can be for a short amount of time. It cant be deeper than just a drop though. An IPX5 and IPX6 mean that the product can resist jets of pressurized water. It is important to note that a product rated to be fully submersed in water cannot necessarily survive pressurized water jet.