I think a fundamental problem with the dating argument is that (I assume) IAJ believes the Hebrew Bible to have been authored by Moses, and assigns a date for that based on his view of Exodus.
So, this would bring in the historicity of Moses (and the Exodus) and greatly widen the scope of the debate. That is, if IAJ assumes that Moses was the author. I think this is a brick wall, because IAJ will not be able to bring evidence (outside of tradition, say) of an extremely ancient origin for the Hebrew Bible, and Butterfly won't be able to accept that IAJ takes the tradition that Moses authored the texts as evidence.
At least, that's my assumption at this point. Could very well be wrong.
Edited by Wollysaurus, : No reason given.