If the puck light has the switch close by and you can access the wires for it, it may be easier to pull a wire to the light's switch rather than make a home run to the distribution center.
Your distribution panel probably has a vacant fuse slot. I would use that and fuse the fan's power wire. You'll also need a ground or (-) phase wire connected to a ground terminal. There should be either a (-) terminal on the back of the distribution space or a group of wires connected together. You could also capture (-) phase at the lamp fixture.