A:AnswerThe Sonos speakers are WiFi and communicate with each other or your phone or tablet wirelessly
There are battery powered Bluetooth speakers out there. BestBuy has them. Even some that are rechargeable
Good luck
A:AnswerNo the play one does not. The Sonos One has Alexa built in. You can however control the Sonos Play One with any Alexa product including the Dot.
A:AnswerSonos has a desktop app (http://www.sonos.com/en-us/controller-app) that can play local content and apps for playing podcasts, but it doesn't have an Audible app for direct playback of audio books. They do have integration with Amazon Prime music, so I imagine it is only a matter of time before they work out the problems with Audible integration.
A:Answerno, none of the sonos speakers are bluetooth compatable, only wifi. you can line in on the play 5 via the auxillary input though, so you could get crafty and hook a bluetooth adaptor up to that one if you liked.