Anytime you can do a longer spring by just doing rivets, you should, especially with it stripped bare like yours. Extending rearward isn't bad. I always thought cruisers looked like they were humped up when lifted. Pushing the front forward is good too. Keeps the tires out of the body. Just make sure you don't screw up the steering box and linkage angles. Lots going on up front when you change wheelbases.
Make sure you do the Marlin or Trailgear inner axle seals. Pony up to ditch the factory front brake line setup so you don't have to crack the lines to fix a birfield. It's a not important, until it is, kinda thing.
Talk to George about twin stick t-case. Having 2 low sounds like overkill till you are on slabs of rock but you want to creep along. Buy the t-case saver.
For steering, 80 series ends keep it Toyota but they don't have the angularity capabilities that Chevy 1-ton stuff does. I think that is what kept braking Keith's Pittman arms. Same price when you are building from scratch.