The ROTJ urban legend of ships crashing into the Death Star shield can be explained not only by the novelization, but by a much more likely source for us then-young-kids: The Read-A-Long Cassette of 1983. The narrator specifically tells the listener that Lando and the Rebels pulled away from the space station, but some of the ships exploded because they hit the invisible shield.
The first time I read the names Coruscant and Palpatine was not in any EU material in 1991. For me, these names first appeared in the rulebook for Star Wars: The Roleplaying Game published by West End Games in 1987. In fact, both of these names are on the first page of the book in a simulated opening crawl. I believe one or both of these names may have also appeared in the original preface to the Star Wars novelization in the beginning in that "From the Journal of the Whills" page...