Why?
Walls - You've obviously got talented fab skills, and a pile of great parts, but I have to ask why that parallel 4-link suspension design with the huge center drop?
I feel like I'm missing something? The factory suspension is already a great platform for an excellent multipurpose rig. Add rear 11 pack leaves, Duff's extended arms, F250 shock mounts, quality shocks of the right length, get rid any binding, and articulation approaches amazing - while still retaining excellent road manners - and all without losing the ground clearance it looks like you are giving up with your design.
If you hate the stock design that much, go with Duff's rear 4-link, a custom fab'd rear triangulated four link with a horizontal / cross-member style mounts, and then a three link front.
I know you said it mostly street and beach, but it looks like you are putting a ton of time and effort into fixing a problem that doesn't exist, and you might actually be hurting trail capability if you, or anyone else ever plans to wheel the truck anywhere besides the beach.
Not trying to be a jerk, but had to ask....with those axles and that suspension design...I think you are secretly building a Monster Truck... haha