no, its not.
those are interesting details, but it's no proof that the peace feelers actually had the authority/power to negotiate a peace treaty.
more details are found here:
https://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x8785716takeaways:
- there are always peace feelers in any war. this does not mean that they actually represent the majority opinion within their administration and actually have the power to carry out a surrender.
- the newspaper in which this article appeared was very biased and anti-FDR.
- FDR dismissed the initiative and MacArthur because he didnt trust MacArthur's instincts as a politician. The subsequent Korean War and MacArthurs involvement there confirms this view.
So yes, I concede that you have a point here. It's more questionable than I thought whether Japan would really have fought to the bitter end without use of the atomic bombs. But the sources you gave here are far from being "hard proof" for the contrary, for the assertion that a Japanese surrender would have been a sure thing if only the Americans had agreed.
These 'peace feelers' were from the newly instated government whose mission it was to bring about an end to the war.
There's plenty more evidence and the vast majority of historians agree with my assessment so... I could be wrong but I think it's foolish to conclude I am without some pretty heavy evidence to the contrary. Of which there is little.