Subsequent to the smoke is gone and only the smell is left is it considered secondhand smoke?

Yes: The residue has toxins in it as well, and gets on walls, surfaces, clothing etc. This does not cause problems except if someone is "intimately" involved with touching those objects, children in particular. Some of these toxins can go through skin, and can still be breathed in. It also gets into neighboring apartments and other connected areas (hallways etc.) and is a public health risk to many.