hamptor,
like others have said, the bees will clean this up.
question 1 about the dead bees with heads in cells: i gently tap the frame to shake out what i can. the bees take care of the rest. (remove the dead bees, clean and polish the cells).
question 2 about the mold: sometimes i will take a wet warm cloth and remove the mold as best i can off the frame face, and i also scrape any mold off the tops of the frames with a hive tool. the bees take care of the rest....
no need to replace foundation.