Not being critical of your design. Just saying it appears a true four would be possible for your opinion.Thing is, the dog bones are only 3 link, which really isn't bad. I suppose you could mix and match brackets to get a true four link.
But do we really need it? The Pete set up I did is basically a "truck arm" suspension and they work very well, so well that NASCAR still uses them today. The pan hard bar on this is twice as long as it needs to be.
The trunion (that is usually removed) has holes directly above the bottom link that would line up to make a single axle into a four link, making the outer upper axle mount (for the bone end) where the spring was. It would be a true four link and have exactly the same drive shaft geometry as the existing 3 link. Bobbing gets the extra bone.