I just stayed at The Ritz Laguna Niguel two weeks ago. I thought I died and went to heaven. The property is spectacular! It is immaculate clean, service is superb. The grounds and views are breathtaking. If I had to get married again (someone shoot me) that's the place. And I live on the other coast.
As far as the rock, everyone will give you different opinions. No need to go to Tiffany's. I'd say get the stone and the setting separately. Make sure you deal with a reputable diamond dealer. I think B-Line can point you in the right direction. He's in So Cal. FWIW - you do know doubling the size with the clarity she currently has is going to cost alot more than double depending on the color.
Get ready for the CZ peeps to come out of the woodwork.
Congrats