"2.) what techniques can you use in a narrow aisle?"
Throw a backhanded strike to the temple. If he moves to block, grab his arm and step through him, doing a linear version of robuse. If he doesn't block - hit him again!
Also, tenbin nage done by stepping across his body may work, but that depends heavily on angles.
Irimi nage also comes to mind. Especially a straight in version stepping through with the inside leg. That one is especially nasty though.
Use with caution.