Finally Done!
I HIGHLY RECOMMEND THIS SETUP. it's badass. Granted, it took a little extra work to correctly mount the cable at the front diff (and the way that I ended up doing it may or may not be helpful to others, since I imagine not many folks have 80-series locking axles with their factory suspension mounts all cut off, and then mounted underneath leaf springs on a 60-series rig...) but I'm sure another mounting system could be figured out.
Here are pictures of the where/how the cables act on the differentials themselves as well as where/how my hand-lever controls are mounted:
Rear. The cable pushes lever towards the left about 2", and that acts on the shaft which actuates the lock-collar inside the diff. In this picture, the lever is vertical and the differential is unlocked. The installation here was very easy since the chilkat cable bracket fits directly on the top of 9.5" differential.
Front. The cable pushes/pulls downward/upward on the circular-lever, which rotates a gear inside of the diff housing that actuates the shift collar in the 8" high-pinion front diff. This installation was more complicated, because the cable-mount bracket that chilkat uses does not fit on the high-pinion 8" (the actuator does fit, just not the cable-mount bracket) because there is that large ridge in the top of the housing. The ridge also blocks the path of the cable from being left/right and necessitates it being up/down. I fabricated an additional bracket that both cleared the ridge and provided area to rotate the chilkat cable-mount bracket about 45d so the cable pointed at the circular lever at the right angle.
Hand-levers mounted. I found this horizontal position was pretty much the only one that fit within the spaces I had while also pointing the cables toward the port that they exit the hull though (which is a factory port, usually just covered, basically in the dead-center of the FJ62, underneath the back-end of the center console, roughly even with where the front seat belts attach to the floor). It was also fortunate because logically the lever that controls the front differential is mounted in front of the lever the controls the rear, and because the cables could be easily routed underneath the passenger seat, without any obtrusion into leg area. Both bulkheads are bolted together using 2x 3.5" bolts (one of which also serves as/replaced the fulcrum points for both levers) which also are used to securely mount the bulkheads to the center console.