Hey Erioshi, good comments. Opinions and advice always welcome here.
I always imagined the type of lower wishbones you're talking about and for a long time that's what was in these drawings. I really liked the simplicity of the single bolt holding them on, It seemed easier to provide one strong mount location then two. I wanted everything in the rear built around a strong roll bar bulkhead.
I moved away from the wishbone and went with the parallel links because I was having trouble working out the bracing under the rear ward facing hoop, they also offer the advantages of being easier to set up, no toe change and adjustment of rear wheel placement.
It took me a lot of work to find a bracing scheme that I liked and it now turns out that it would allow the rear wishbone you describe. So I think I may revert to that and it will make the bracing a small step easier to work out also. I hadn't noticed I could back to that, good catch.
I did check for interference in a normal range of motion with a little to spare but not for something like spring or coilover mounting failure. I will try a little harder for that.
I am having trouble actually locating the coilover and I didn't expect that to be a problem when I started.