I'd start with eBay-France since the gun is an antique and essentially unfireable. Collector interest in the US is generally weak.
i.have.a.j-reynolds-double barrel 16ga belguim rabbit ear shotgun seaking information
Not enough information
Valenciennes is the region in France where it was made. "Morin" may well be the maker, although I do not have a reference on that maker specifically. There were many French guilds producing arms in the mid-1800's (1860's time frame when pinfire was popular). Value is going to depend on the overall quality, amount of decoration and condition - could be anywhere from a couple of hundred to well over a thousand.
Have you tired the internet?
Impossible to answer without more information.
A shotgun barrel with a cylinder bore choke.
Sold by Sears Roebuck. Probably manufactured by Stevens.
yes a rifled shotgun barrel or smooth shotgun barrel
This would be an early H&R shotgun from 1905-1940, or thereabouts. The 36" barrel makes it more interesting.
You can find information for the 16 gauge Worthington Challenger single barrel shotgun at most gun stores and pawn shops. Many of these stores offer free appraisals and have knowledgeable clerks.
Buy Shotgun. Buy Shotgun.
Without knowing the maker or the markings on the barrel/breech, you can't find out anything. Even then, there may be little to no information.