Good news, bad news.

Good news, looks like you got everything in Nuke right Nice job there can be tricky to get the basics in nuke when you first start.

Bad news you are missing information from the render passes (it's just not there so nothing you do will fix it) if you set the viewer to say direct diffuse you can see the colour information for the main house is not there.

My best guess you are not using the mila material for certain shaders, the new pass system ignores any other type of shader and just renders that out black which is what seems to have happened here.

If you check out the matte passes generated there also some missing. I think your only problem here is the materials used in maya, upgrade any mia_materials to mila materials, render a 720 HD test and read in the new file issue should be solved

All the best
Dave