I'm a little shakey on the dates, but I think around the time you're looking at the Daemonfey of House Dlardrageth should be in the actual Myth Drannor at this time, giving you an excellent villian to use (though you may have to level them a bit)
I was once inspired to a similar idea after reading a Dragon magazine article (sorry dont have the number right now but I will attempt to find it later) about lesser Seldarine Gods of magic. One was Dahral Firecloak, but the one that got me thinking was the elven god of Mythals (dont recall the name) who was weakened by an attack by Malar and is "asleep" in the Velarswood, or wood of sharp teeth or something. Apperantly much of his essence was trapped in a ring which is somewhere about in the Realms now. If the ring was recovered and used to revive the god I imagine it would be a good step in getting him to help "repair" damaged Mythals such as Myth Drannor, Or others. I liked the idea but it is a bit more high powered than I usually like to play. I will attempt to find the Dragon magazine and post again if anyone is interested. Green Knight