What file format is needed?
.ai, or .pdf is the preferred file.
What resolution is needed?
Will depend on what's being printed. If the image has to be significantly scaled, the highest resolution available is always preferred.
Is a bleed needed? if yes, what is the size of it?
Typically, a 2 inch bleed (top, bottom, left, right) is needed.
Does the printer need a layered file or a flattened image?
A flattened image will work fine, assuming there are no changes that need to be made to the image. Changes should be made by the designer and then forwarded to the print provider as a flattened image.
Does the printer need the pictures that are integrated in the design?
Yes, however would like to get a bit more clarity on this question.