My internet was out last night so I'll add some comments this morning---

First--as I see it--you don't have any diffinant plans for this because you have shown a scattering of pics of several cars--at least you are still looking at possibilities and trying to work out the best procedure to do this

Sooo----post 15-----if the perch bolt doesn't fail first----the bracket will fail from the perch bolt holes to the corner of the yellow plate that bolts to the axle---

Post 11----since this car isn't a 4 bar---there is no reason to go to the effort they did to build it like the pic

If you want to use your axle--first make absolutely sure that you can get hubs, bearings and brake components for it---

NOW----if you aren't going to use a 4 bar radius rod--bolt radius arms to the flat spring perch on your axle, adjust caster with axle shims(like it was) and weld bosses to the top of the axle for the spring shackle to atack to( maybe out at the turn up and use the spring in your pics) and if necessary convert it to front steer( or maybe even put a rack mounted on the radius arms)

If you are into welding and you want to try something different---weld a vertical piece to the axle for the spring perch bolt and bat wings to attach to and you will only be offset from axle cross center by a inch or so instead og 4 or 5 inches