Visit the Scent Bar in LA. Its a definite must. You will be able to get your Amouage line there and everything else niche. When people refer to Luckyscent.com here this is the actual storefront. You will get lots of samples if you purchase one of those. Heres a link with the address: http://www.luckyscent.com/scentbar/
Guerlain has a Boutique in Las Vegas, I think Dior does too.
Every city you listed will have a large shopping mall selling pretty much everything on your list with the exception of the oils and the Djedi.
As far as traveling with these frags, you will have to put them in your checked luggage. You cant have more than 15-30 mls of liquid in you carry on luggage on a plane or you will have to throw it away or mail it to yourself.
Enjoy your stay in America!!! Welcome!