Battery relocation

I don't know about fusing that bad-boy, on account of the starter can pull a lot of amps thru it.
And I don't know about fusing the alternator output
But if you run that wire to the back, you'll need to run it thru a big HD relay, else the car won't shut off with the key/master switch. Also, if you're planning on a battery cut-off switch, you'll probably want to use a double-pole type to run the alternator output thru one side.... for the same reason; namely so that the engine will shut off when one of the boys slams the handle in.
If you've done a careful job of cable routing, I can't see needing fuses