"It doesn't make sense to build underground windows!"

Of course not, but when that building was constructed (along with its windows) the ground level was 7 or 8 feet lower, as the photo shows. You don't really think the Mud Flood did that, do you? Somebody with a backhoe did that. Buildings have their underground levels dug out and exposed all the time, or filled in with gravel and topsoil.

I'm not trying to discredit your overall theory, just pointing out something which to me doesn't make sense. There could very well be merit to this idea, but that particular building does nothing to advance it.

I think it's awesome you have found somebody to move to your location and help build! I hope it goes amazingly well :)