Neumann Freres was in business in Liege, Belgium from 1863 until 1957. Thousands of their double-barrel shotguns were imported to the US (marked with English "Bros." instead of French "Freres") prior to WWI. Value to a shooter = $0, to a collector = $200 (but only if in as-new condition), to a decorator for a mantlepiece = $125-$150.
Not enough information.
Look up the Marlin shotgun with the same model number.
There's a whole shelf of books on firearms in your library. Or you may find information on www.savagearms.com
Have you tired the internet?
Impossible to answer without knowing who made it.
Manufactured by Crescent Fire Arms, sold by Montgomery Ward.
Go here - http://www.wwgreener.com/
You can always go to wikipidea