I've found the credits of the Gold version:
Aleksei Andrievski: Clouds of Xeen, Great War II, Wizard's Land 1, Wizard's Land 2, Wizard's Land 3
Charles Watkins: Ghost Planet, Colossal Cavern
Grayson Towler: Betrayal, Gates of Hell, Plains of Aekon, Slayer Legacy, The Road Home
Greg Schneider: Grim Reaper, Dead Dragons
Jonathan Watters: Alteris 1, Alteris 2
Julia Skipper: Roc 'Round the Clock:
Lance Wood: Leopoldville
Peter Mayewski: Merry Men
Phil McCrum: Dungeon Below, Go Ask Alice, Mire Straights, Riddle Me This, Sudden Siege
Rich West: Black Forest
Timothy Duncan: Last Hope, Ludicrosity, Quadruplets, Threedom, Thunk
WongSui Jau: Family Reunion
Plains of Aekon was too made by Grayson Towler, the guy behind the Betrayal map. I am guessing there are more Game Of Thrones nods in Gates Of Hell, Slayer Legacy and The Road Home.
If I recall correctly, Gates Of Hell is a multiplayer map rather than a scenario, it can be played in single player by creating a hot seat multiplayer game, then, right at the start you save the game, go in the main menu and load the game in single player mode rather than multiplayer mode. The other players will be controlled by the AI. I believe the difficulty level can be tweaked, like in the first game, by giving yourself an handicap while you select the rules of the multiplayer game.
It's also worth noting that Timothy Duncan's Last Hope and THUNK were the first and second missions of a seven missions long campaign. The remaining missions are available online.