the comparison of your real living room and the simulation is amazing!
Great work, I really think all these details add a lot to the realism!
For the resolution of the scene, you could perhaps try to work backwards from the resolution and the field of view of screen you want to project it to (e.g. if it were a screen with an horizontal resolution of 2000px and a horizontal FOV of 90°, your cube face which is 90°x90° would have to be at least 2000x2000px after the pfilt). If it helps, @Jan_Wienold and I had tested the FOV of our VR headset with a nice trick where Jan made a scene with concentric circles at 10° steps and we could count in VR how many we could see in each direction.