Yes, I was extremely surprised about that. The existence of Jesus—as a historical figure who was a Jewish apocalyptic preacher in the first century—is well-documented. It's not even a matter of debate amongst the scholars now since the likelihood of Jesus' existence was established long time ago. As far as historians are concerned, the actual existence of Jesus is the most likely explanation for all the evidence we have.
Having that said, I was really surprised that they didn't talk about it in more detail. The whole Awake publication could have been about Jesus' historical existence, yet all it suggests is something that would convince literally nobody. I bet it was written by someone with no historical training whatsoever. I mean, citing Albert Einstein? What the heck is this all about? Recently, there have been two scientists—very good published scientists at that—who talked publicly about how Jesus' did not exist. But that's all they were: scientists—with no knowledge of history.
Now, when it comes to the other three persons, Michael Grant, William Durant, and Rudolf Bultmann, I wouldn't necessarily say it's wrong to classify them as "experts." William Durant was the only historian of those three; Michael Grant had a degree in literature, and Rudolf Bultmann was a theologian. And although literature and theology are not the same as history, they are still fields relevant to Jesus' existence. Nonetheless, it does surprise me that they did not cite actual experts like Bart Ehrman, who is one of the leading scholars in the field of the New Testament studies. He additionally specializes in textual criticism and has training in history. But I suspect the Watchtower was unwilling to cite people like him because... they are atheists who were convinced of the lack of consistency within the books of the Bible because of thoroughly studying it.