After trying all the sensible methods of removing the float pin, I had to resort to senseless force. I had already ordered a new pin and floats in case it came to this.
I used the Dremel to cut a section out of middle of the pin, and the float along with it. The headless part of the pin pretty much dropped right out, but I had to take pliers to the piece with the head and wrestle it out. Carefully. Sheesh.