Turalyon disappeared off the map completely. We have yet to see him in-game, or find out what happened to him. He became a non-entity even before Arthas betrayed us.
The Alliance of Lordaeron Arthas and Turalyon were a part of was *technically* a different political entity than the New Alliance today. Though I'll concede I'm nitpicking there.
Illidan was never part of any Alliance. Ever.