I'm thinking about shaving the emblem on the front bumper I'm about to paint. What would be the best way to do this?

I've just shaved them on mine.
(1) Pop the emblem off (it's being held on two studs and little glue). Mine came off very easily.
(2) Either get old soldering gun and piece of polyurethane and "weld" the holes shut or take a piece of polyurethane and (using some very good glue) glue the pieces on the inside side of the bumper.
(3) Bondo over the welded holes and sand with (max) 240 grit

Then you are ready to paint.
If you skip step (2) the bondo WILL sink over the time and you will have two dimples in your bumper
Hope this helps.