Google did indeed de-index that page after I moved it from published to draft. Because it was removed from the XML file and it was no longer accessible, it disappeared off Google's radar.
It may or may not make a difference, but IMO I don't think it would matter. Googlebots will crawl your site everyday, but it's a matter of how deep your pages are (accessibility). If this post was 3 levels down, it likely will take longer for it to be discovered again. I did not tweet or share this the article after it was republished, but would likely get noticed quicker if I did.