For some unfathomable reason, scientists and journalists claim there's billions of bugs and bacteria that live in the upper atmosphere but don't provide one microscopic reference to any actual species of anything. Does anyone actually know definitely what specific animals actually live in the upper atmosphere or is it all a hoax?

Without a reference to these claims, it is hard to know what (exactly) you are referring to.

But here is one paper: http://www.pnas.org/content/110/7/2575

And another: https://www.ncbi.nlm.nih.gov/pubmed/19643890

 

And a few thousand more here: https://scholar.google.it/scholar?q=bacteria+upper+atmosphere

Ran across that first paper as well.

 

 

 

 

Not sure whether anything stays up there indefinitely though. Just through random chance you could expect to eventually reach the bottom again. Well known though even larger animals like spiders can travel extreme distances before landing.

 

I'm curious how things will evolve as blimp satellites and similar become the norm.