Each star should fit on a makerbot, the stars.stl is one file with all 10 stars on it, but you better have a big bed to print it! it is a 3 hour print for me but than you have 10 Shurikens!
The magnets I am using are
I put two magnets opposite facing for the big spots.. and crazy glue them all in place. I have not found any fridges that have a polarity so this has not been an issue. Oh, Hopefully your prints come out better than mine, it takes me about a minute a piece to clean them up with hobby knife.