Assuming the rear batteries are next to each other, then you don't have to fuse them.
You will need 2 1/0 fuses for the + run from front to back. Another if you want to fuse the Big-3, another two fuses if the batteries under the hood are on opposite sides.
You will not need distribution blocks, because the batteries in the rear can be used as such. Additional fusing on the amp wires if you would like to be safe, or if the amps require external fusing.
Therefore, 95% of your wiring should be 1/0. Add in how much wire you think you need for each amp, depending on their location in relation to the battery.
1/0 wire should be ordered as such: 2 runs front to back (+ and -) I would use bumper to bumper as a measurement here. Assuming your batteries in the front are on opposite sides of the hood, then, if you can get a straight shot safely, do 2 runs (+ and -) of the width of your car. If you need to go from the front left, to the firewall then across, then back to the front right, factor that into your measurements.
Big-3 is another addition to your wiring. 1' for battery to ground, the other two are very car dependent due to different locations of the alternator and grounding strap.
-Matt.