I have a somewhat shaded patch of turnips, flax, and barley, under some black locusts.
so far it looks healthy to me. I planted it densely, using pigs to loosen the soil and turn it all in. I don't expect the turnips or flax to be human food, but I am hoping for a barley yield.
The barley is the green in the center, rear.
Rye etc on left, beans squash sunflowers etc on right.
The polyculture is no problem... The shade might hurt it, we'll see.
Pic 2: I have a patch of wheat etc on sandy soil, also under locusts looking quite nice, but the timing is so different, the wheat being nearly filled out already.
Pic 3: I put rye in my hugelculture beds to hold things up. They do the job, and yield big grains of rye, but not many, since they are just planted here and there.
Note that the Jerusalem artichokes in all of these polycultures don't seem to be hurting a soul.
Sorry the pics are so low quality.
I would love to see pics of whatever you come up with.