Correct, according to canon there was no ecological disaster. The site was different in that it agrued against the canon, based on a very wide variety of canon facts - basically, everything in the canon suggests that there should have been a disaster, except for the direct evidence that there wasn't - all the technology, all the visual evidence from the movies, and all of the known stats point to a necessary disaster.
The shield idea is neat, but a bit iffy - it was designed to go up and encircle the battle station, i believe guided at least in part by mechanisms on the station itself, and changing it to a flat planet-covering condition would have been pretty tough, especially since a lot of impacts would have come pretty rapidly after the explosion (bits aimed directly at the planet).
Hrm, wait, was the big hole oriented planetward? that would definitely help, then the might have been caught by the odd greavitational fields of the planet (which is mentioned as having odd gravitational effects that make hyperspace travel through the region messy, one reason it was picked as a secret location to construct the DS2.)
AFAIK, and as far as the pretty extensive research this fellow carried out states, there is no canon explanation of how Endor survived, it just *did.* I hate pointing out flaws in Star Wars, I'm a big fan, but that to me seems to be one. (at least there was no "big red button" on DS2 like there was on DS1, although among other big red buttons, a heavily shielded, turbolaser protected exhaust shaft is very reasonable)
Hrm, DS1, DS2 . . . DS9?? Makes you wonder, eh?
