Continue: Setting this light to 200%, or 500%, or even 1,000% intensity (1000% used in the example pic) with an ISF intensity distance set to 2 inches creates more of an illusion of a lit lantern in a darken room, but the light does not pop out of its confined space with the glass panels of the lantern set at 98% transparency. It doesn't light the room. Modifications to the design of the glass panels to make them all one sided facing out then does not trap the light, but then the wanted glow is gone.

My best guess now is to add a shot light pointing up within the lantern to create the ceiling lighting effect and another spot light pointing down just under the lantern to light the figures and table.

Obtaining this flame glow in some form or another within the lantern's glass structure and lighting the room is the goal without doing any post rendering in PhotoShop. I know cutting a lantern out of one pic and adding it over another is not difficult, but that is not the point.