The chemical used in the movie to bring back the dead 2,4,5 TRIOXIN is a real chemical. It's real name is just TRIOXIN and is used as a morticians restorative chemical to repair cells and maintain the corpses contours after postmortem tissue constriction.
In the film Frank says that all human skeletons for teaching and research come from India. This was true, but shortly after the movie came out that practice ended and real skeletons are now much harder to aquire. It is not known whether the film was directly responsible.
The names "Ernie" and "Bert" used together in a pair is indeed synonymous with "Sesame Street". However, Jim Henson named them thusly after the policeman, "Bert" and cab driver, "Ernie", from the movie, "It's A Wonderful Life".
Ernest Kaltenbrunner was the head of the German SD (Security Service) during WW2. Ernie is listening to "The Panzers are Rolling Forward in Africa" on his Walkman. He also has a German Walther P-38 pistol!
There is a work print of Return Of The Living Dead floating around the Internet, chiefly on eBay. The work print includes a lot of alternate shots, extensions of already established shots & an alternate ending (which makes perfect sense leading into Return Part 2). If you can, take a look at this.
I first saw R.O.L.D when I was about seven. It wasn't a very good copy. Something always intrigued me and that was what it said on the eye chart in Berts office. I found out a couple of months back. "BERT IS A SLAVE DRIVER"! I love to see films making that kind of effort.