Fuel will come out no matter what. The cap wont make any differece as theres a pump in the way. And dont worry about taking the fuse out, just dont start the car lol. Or if you want to be safe you should really disconnect the battery as not to short anything out and create a spark but its really nothing to worry about I've pumped fuel out of my tank by disconnecting the fuel line and putting it in a bucket the turning the car over lol. Onces its all done, let the fuel pump prime by turning the ignition on, check it, if its ok, Just start it up and check for any leaks again. 👍