Lest we forget, 01net originally published the rumor that Vita's RAM had been cut in half, and we know how that turned out. Yeah, most of their PSP2/Cafe rumors turned out to be accurate, but their track record isn't perfect.
The dev kit stuff sounds plausible, but everything else is a tad far-fetched for my taste, especially the analog stick peripheral - there's at least space in the lower right corner where one could fit in an acceptable position, but there's no port nearby that it could attach to.