Can a Combat Infantry Badge be worn on the Aux. uniform along with the medals?

Yes, only two badges may be worn (one above, one below your ribbon stack).  A mini CIB may be worn on dinner dress.
The Combat Infantry Badge is not one of those allowed on the ODU. By extension, this also applies for the Working Blue uniform and the Hot Weather uniform (i.e., only the Coast Guard dark blue short-sleeve shirt alternative).