It is true that JWs sort of believe in sola scripture. Where they differ from the Protestant tradition is they do not believe that correct interpretation of the Bible is available equally to all. For example the October 1st Watchtower 1994 was about the role of the Bible, and included a box titled: "Channel to Understanding the Bible". In this box it states: "All who want to understand the Bible should appreciate that the 'greatly diversified wisdom of God' can become known only through Jehovah's channel of communication, the faithful and discreet slave." (Page 8) This seems to be at odds with the Protestant idea that a right understanding of the Bible text is available to all believers unmediated by any church authority.
On the canon of scripture accepted by JWs. I think there is a good argument to be made that Origen listed the Potirpestant canon over a hundred years before Athanasius. Origen was a subordinationist and arguably better aligned with JW Christology.