Yeah, agreed there are a lot of questions there. But, I also agree that's a good amount of light for what I assume is a pretty small interior, especially for a 1920's living room.
My suggestion from the limited information is yes, block direct sunlight from outside. Put the screen fairly close to the window- assuming it covers the window- with enough space for the kino flos- you want enough distance between the kinos and the 4x4 that the screen is evenly lit. You're looking for 50-70 IRE. The exposure of the interior is up to you.
The M18's can be behind and above the screen going through some moderately light diffusion, focused to the same spot on it to simulate a single source. You can fire a joker into the ceiling for general level, and perhaps something like a book light for a key with the others- depending how wide your shots are and how large the living room space is.
I don't know if any of this would actually work but first thing that popped into my head without seeing the space.