There are key things missing from the leak. It's possible to build some complete drivers, a lot (maybe all?) of the ROM, and some critical pieces of the system, like the boot code and DA Handler. But source for some other parts, including the 68k interpreter and the virtual memory system are missing. I don't think a complete build is possible from those sources, but it would be possible to build some of it, and take the rest as intact resources from the system file of a working system. That would be an interesting exercise. Maybe somebody has done it. But just figuring out what is there and what is missing is a pretty big job.