Catt,
The problem with the motor is a very simple one to fix. Take off the shell, and on the light board you'll see a pair of little bronze clips. These bridge the connections you would use to install a decoder. Pull off the clip, pinch it together a bit so it snugs onto the contact more firmly, and that should bring your engine roaring to life.
Just make sure you put the same clip back where you found it.
The coupler install takes a little creativity and some scrap styrene... I also added on the foot boards at the bottom of the pilots.
Lee