Yes to the safes in your cabin, you can set the 4 digit combo with what you want. Its small, but still large enough to get a camera in there if you want...
I know there are definitely "Coke" products, in fact the people with the coke cards had a nice coke bottle for their drinks for the week, me, I'm a Pepsi person, but I just drank iced tea all week and lemonade, which you can get for free in the windjammer during lunch... You can also get apple/orange juice in the Windjammer and main dining room for breakfast, no problem. They only will charge you for them if you order them through their bar service, but no charge if you purchase the soda/juice card.
You will have a ball on this ship, what itin are you doing? Just be sure to get your tickets for the ice show, the one show you \don't want to miss.