Thank-you, Thank-you!!
Those are all great suggestions.
I am doing a test render now with lower GI, and I think it is getting better illumination-wise.
I don't think the GI contribution would be 0.00 even if it is midnight, considering there's lights coming such as from your neighbours, security lighting of the building next to yours, and the brightly lit moonlight on a clear night ...etc.., and of course there are also artificial lights turned on inside the room and those lights also bounce onto surfaces of different reflectance values.
(And I find it strange that many residential lights were still lit up brightly at 2AM in Hong Kong, and midnight was still so bright over there.)
A lot of families in Asia have bamboo furnitures inside their house, and bamboo is a nice replacement of wood because it is fast grow and it is durable.
Ah, the base for the floor cabinets, I forgot about that! Since it is sliding door, I just assumed you'd use the foot to slide it open.
I don't want to make this particular drawing look like a model house, just want it to look like a typical sort-of-occupied home (but of course I don't have a lot of little things in the scene to fill it).
Thanks again for your input, I shall rework on this some more.