Please forgive the terrible camera on my phone but attached is my (probably) final fabric choices. I had about 4 different group options with mainly differences in my C fabric, and some choices in the E & F family fabrics. I have a few concerns about my final choice here- neither E1 nor E2 are actually tone-on-tone and there's not as much contrast between their tones as I'd like (more medium-dark and dark than the called for medium and dark) Also, only E1 and F1 have a triangle/diamond pattern whereas everything else has a circle (it might be hard to see but D is yellow with tiny white polka dots, F2 has tiny slightly-lighter blue bubbles, and G is white-on-white medallions) Plus I think F2 counts as a directional fabric, although I think I'd be fine with not having all the triangles pointing the same way in the final product, assuming that doesn't throw off some design element.
Ultimately though, I actually really like the final group of fabrics I picked out. I can just see how there's room for it to potentially go poorly depending on the actual pattern. But I guess that "what if..." factor is part of the fun of a Mystery Quilt lol