All very good points, but sometimes it’s difficult to tell how much power you have in the hiring negotiations with a potential employer. Asking too many questions like the ones you’re suggesting could be a potential turn-off for an employer since it might show a lack of trust. It would be a negative indicator for them since “hiring for culture” is such a prevalent factor.
Really, the best option is to consult with a confidential third party who can do this sort of credibility research on your behalf. It’s possible a potential employer would do the same on the candidate, anyway.
That said, spending a few minutes searching through the web and social media to do your own due diligence is a good idea.