Found your 1st flaw. Walls are made from brushes and resolution is 512. A brush’s lightmap resolution works the other way. The lower the value, the better the lightmap quality wi;l be. Default is 32. Trying with a value of 2. (or try 16, 8, 4, 2)
You have over 50 brushes with very high lightmap values. That’s most likely your problem 
Also removed the yellowish tint on some lights!
Also, you still had the Koola’s scene and yours side by side in the same ‘‘map’’, it’s going to raise build time for no reason.
I’m rebuilding with higher settings and proper lightmap resolution. I’ll post results