I think you'll find a lot of good food choices in the US, much more variety than you are used to. I wouldn't bother trying to acclimating them to US food now, because virtually nothing that we sell here is available there, and you'd be ruling out most of the really good stuff by doing so. I'd just recommend bringing a supply of the food they like here, then transitioning them at that point.
There are two really large pet food chains (Petsmart and Petco) that you'll see everywhere, which are good places to buy supplies and litter etc., but bad places to buy food. They mostly carry cheap, crappy food. Look for the small "boutique" kinds of pet stores (fortunately they too are all over). One such place I know that is up there is called "Mud Bay"
http://mudbay.com/They are in both Portland and Seattle. They aren't my favorite place to buy food, but they are good. (It's actually a pretty great luxury that I can recommend my 3rd favorite place to go with no qualms at all).
Here's a bunch more places to check out (I basically found them by going to the radcat website and checking out "where to buy". You and your cats may or may not like Radcat, but a place that carries RadCat is likely to be a pretty awesome high-end kind of place that caters to cats).
http://www.radfood.com/where_to_buyAs far as particular foods go, if you go into these types of places, most of the food there will be pretty decent quality or better. You can just go in there, explain that you are auditioning new foods, and many of them will send you home with a lot of samples and suggestions. There's always new ones to try, which is kind of fun. Many of them have freezer sections where they have all kinds of raw stuff to try. You mentioned that your cats didn't like the raw when you tried it. I wouldn't completely give up. Just like any foods, some taste better than others to cats.
Brands I'd recommend to try:
Weruva (canned)
Earthborn Holistic (canned and dry)
Go (canned and dry)
Tiki Cat (canned)
Rad Cat (a commercially available frozen raw mix)
Orijen (dry)
Weruva, Earthborn, and Tiki Cat have particularly great fish flavors (or so says Serafina anyway...)
There are a zillion and one litter choices here. You'll find one you like. I'm a fan of TidyCat, and I supplement that with some of the wheat-based litter. TidyCat is clay-based, so not very environmentally sound, but texture, smell, and clumping are top-notch, and after trying a bunch of other stuff, that's what I settled on. But there is no end of choices here.
If you have other questions just ask. I live in Portland which is not that far from Seattle.