Create image which is filled in from another image? How do I blend two images - using the outline of one and the coloring or background of the other?
Everything you want to do and more is available through the use of Photoshop Layers.
It's kind of beyond the scope of the forum to teach basic Photoshop layer usage, but you can find many tutorials online, and Photoshop itself comes with decent documentation (Help).
You can, for example, open one image, paste or place another over it as a second layer, then you can blend the two through many different Blending options, as well as 0 to 100% blending percentage. You can even use transparency or masking to make parts of a layer transparent, opaque, or anything in between.
Using selection and refinement tools, you can even put subjects on different backgrounds...
As Noel just said, there are "lots" of options.... just depends on what your trying to create.
make a selection / get an outline of the "one item",
add a new blank layer and while the selection is still active, on the new blank layer, copy and paste, or drag and drop the "coloring or background" from the other document you are referring to.
You can drag the selection onto another empty document, and fill the selection with the coloring or background.