I spoke to Darrell today, who is a Customer Engagement Analyst at Kobo. He said that the Vox was not designed to be recognized by ADE - and they don't have any plans to make it be (although, I asked if he could ask the development team, as he sits in round-table discussions with them).
The overdrive app is available for download on the Vox. I was able to do it myself and I can read my library books from there. I would rather sideload my books to the Kobo app. from ADE so I can use Pulse and Reading Life for my library books, but alas - it is not to be. I complained about this to Darrell, so hopefully one day we'll be able to use ADE with the Vox...