@VHamptonthat was a good idea, but unfortunately, the 3D poly line features in Pro are very limited. I can't create a generic 3D box using the drawing tools. HOWEVER, I did find a way around this. In the library browser, I found the "box" in the the geometric "shapes/boxes." Once placed on the plan, the box can be made any dimensions and moved to any distance from the floor. The material can also be changed to "Drywall."
I essentially covered the outer wall material with my own piece of drywall.
fberus's post in Alignment Problems was marked as the answer