As for the Mill, it has enough differences that these attacks wouldn't work on it. Just the separation between protection and translation, for example, would stop Meltdown in its tracks.
The Mill is not vulnerable to Spectre and Meltdown.
We have a paper that will go public shortly explaining how these attacks apply to in-order architectures that do support speculation, and how the Mill avoids them.
Watch this space :)
Will you be posting this paper on HN? I'm sure a large portion of the community here would be interested in it.