You could throw in extensions and curls if you wanted to, but very light. If you really wanted to, I guess you could do squats on the assistance day. i would keep it light and fast. 3-4x10 and that's it. I worry about the shoulders and elbows getting beat up from holding the bar on your back 2x per week. With the PL side, I have to keep my bench moving, as well.
Hope that makes sense.