Did not read all the 4 pages but skimmed over them, I went down this road multiple times since 2003 to get where I am now. One thing I can tell you, regardless if you link the rear or run leaf springs, is that bypass shocks are a absolute must. And the larger you get the better they are by A LOT. I now have 3.0 5 tube bypass front and rear and their ability to let the axle move fast when needed and also keep from bottoming is not even comparible to a 2.5. but they cost more than twice as much.
I also highly recommend full width for both stability but also additional room for a much longer track bar to minimize side to side movement.
The rear drive shaft is long enough for more travel than stock eb leaf springs will ever cycle. I ran Ford ranger race pack from deaver. I think they are 10 in longer or something around there. They cycle clean 16 in before leafs start separating and the shackle flops down. I was able to place the mounts in a way that throughout the travel the pinion angle changes only 1 degree and slip yoke plunge is less than 1/4 in. It's a lot of work to end up still on leaf springs but it works.