Oooh, some good questions!
1) Unfortunately, I'm a Creed virgin so I can't help you there
2) This could depend. I have taken perfumes on overseas flights as well as had them air-couriered, and I've not noticed any difference in them. However, I have always had them in the pressurized cabin, not in the cargo hold-- that could be a factor?
3) Just treat your fragrances like fine wines: keep them in a dark, dry place, and bring them out every now and then to marvel at