you will get what your trying to do. It just burns the wood as it cuts. Yes the plug will eject with the next one.
You can NOT use these with a hand-held drill! They are designed to be used with a drill press.
No good for large numbers of plugs. Most times the plugs jam in the tool, You have to manually clear the bit after each operation. If you need dozens o plugs this is a hard way to get them.
1/4" ; 3/8"'; 1/2" Yes they'd work fine to cover deck screw heads.