I have not got any of those dragons (because of lack of profit making) nor have I ever tried. But the results of breeding is random so just keep trying! Plus Storm Dragon gets great money (so keep them) and Quake Dragon does also.
Just keep trying! You'll get there sometime soon. Bluefire and Crystal are never going to go off the game so don't worry! You have plenty of time to get them.
Any special tricks to acquiring the Panlong dragon? I've been trying for months. I have surrounded my breeding island with bamboo, paper lanterns, and pagodas still no luck, just alot of fogs-blazing-muds and worst yet lavas, long breeding and no money to speak of when selling.
Nothing like that ever helps! The breeding solutions are always random and it has not been proven that buying anything to do with that dragon before you try to breed it. Decorations are just there to make your park look pretty, they have nothing to do with breeding.
The best conbination= Mud+Blazing. Fog, Blazing and Muds can bring you lots of money though so its worth keeping them.