interesting build thread, you built a really clean looking axle.
Im not sure why the concern on reusing the spring mounts on the axles, they are under compression against the axle, and not getting a twisting force like your link brackets, actually it looks like there's more weld holding them on to the axle they're probably, much stronger anyway.
As to the bracket at the top of the diff, do you have any concerns with it hitting your oil pan, or did you drop your bump stops etc? My rigs got a 6BT and had to have the oil pan notched for the diff, I can't imagine a bracket like that on top of it, it would cause huge problems for me, but maybe you got all kinds of clearance with your gasser. I dont know, just curious.