Stonewall King

Stonewall King is the bartender of the Napolean House.

Background
Stonewall is friend with Gabriel Knight who frequents the bar. He goes out only after dark. He is very annoyed of the monotonous music of the street musicians.

He invented a drink named "Laveau's Tomb" but didn't become very popular.

Not much is known about him, as he says, the bartender's job is listening to others, not talking about himself.

From Day 1, Gabriel can visit him and question him at the Napolean House.

But most of his information is not relevant to Gabriel's research until Day 3, when some of his revelations that Sam Singleton is a jewerl, and has some knowledge of Voodoo, becomes useful in finding someone to make a snake bracelet from a clay mold gabriel had made.

Gabriel can continue visit him from Day 5 onwards, but Stonewall has little knowledge of any of the new topics Gabriel brings to him.

Behind the scenes
Stonewall is overall a minor character in the game (although he does have his own interview interface and character portrait). There isn't much he knows other than what goes on at Napolean House, and the only bit of relevant information Gabriel can pull from him is information concerning Sam Singleton and his former career as a jeweler, when questioned about Voodoo and Patrons.

The fact that he is an overall minor character might possibly be the reason why he was replaced/name changed with Monty in the novel.