That's the thing, like you said this is all so poorly documented. We're all working off decade old memories here. Websites from that era just didn't stick around in the way things do now.

-Albus, Avalon was definitely a city on Graal classic (or, the adventure, or just Graal whatever ) at one point and there were a couple neat quests there. There was no fountain in Avalon but I think there might have been in the much larger area, Destiny, south of it. I know that was on classic because it was the location of one of the tridents at one point.