If you're using the stand-alone version (not the Unity version), all generated sprite sheets are saved in a folder called "Created Spritesheets" located in the root directory of the application.
To hide a weapon, simply click on it again in the UI—this will toggle its visibility off.
There are several idle animations available. Some are designed to look natural when the character is unarmed, while others are intended for use with weapons. For unarmed NPCs, Idle 3 is a good choice.
Post-processing is applied after the sprite sheets are generated, so unfortunately there's no way to preview the results beforehand, this includes the resolution.