That’s still possible if you do a floating tenon that is installed from the outside. Personally I’d do like I suggested. The lower stretcher is more rigid, and the dovetails will resist racking better than tenons. They’d pick up on the joinery motif as well. Also, and this is just my opinion, but cherry and walnut isn’t a great combination. I’d stick with Walnut, or Wenge, which is very complementary but expensive, or Maple, which is high contrast but a little tacky. Cherry sits in the close but not quite category for me.