1)I like (and use) the 1st one... like it because it's more flexible than the other one, and PERSONALLY I like using the wafer fuses to the round ones... though the round ones are much easier to find (Radio Shack, CC, etc.)
2)Still need the extra 40a fuses, the amps need to be fused separately from the main one that is under the hood.
3)That should work
4)Looks like everything is covered