Wow, what is the engine history here? I'd be very concerned if this engine was running recently, as those heads have absolutely no oil in them! There should be *something*.
That weld looks like it was a repair from a broken exhaust stud that was drilled out improperly. Assuming the repair was done well, its probably ok.
The freeze plug can probably be repaired assuming no major aluminum corrosion on the inside. Even then, perhaps a good machine shop can come up with something.