1. To the best of my research no canon was closed circa 400 B.C although I believe that an argument could be made based on 4 Ezra
2. The Masorectic text and the Septuagint text were closed after the death of Jesus ... you may pick your own date
3. I suspect the closed canon of which you are speaking is the one that Wikipedia refers to as the Calvinist canon.
4. If this is a deliberate attempt to promote a specific denominational family view rather than a broader view, the timeline will quickly lose credibility. I can vouch for the fact that a significant portion of our parish's converts come from this type of sloppiness - an effect of being a University parish.
5. If this is intended to reflect the end of the writing of Scripture written in Hebrew and included in the Masorectic canon, the label is misleading.

Note: I got here from a right hand click on "fourth century BC" in FSB - worked quite nicely.