Do front-end developers need any special considerations for the Amazon Silk Browser because of it's split architecture and it's re-sizing of images? Or can it be considered as just another webkit browser from a developer's perspective?
In general I've found Silk - especially the newer versions - to behave as a pretty standard WebKit browser. Some of the Apple specific tuning isn't there so testing against Chrome on the desktop has been the closest experience (though one caveat there is that Chrome does seem to take webkit fixes faster than anyone else)
I've not seen anything that would indicate that accelerated browsing does anything different for EC2 hosted content - As hosted content often comes from a number of sources I don't expect they'd split traffic on internal and external networks though it sounds like something worth asking in the forums at forums.developer.amazon.com/forums/category.jspa?categoryID=3 to get an official answer