This challenge was *wonderful*. Here's why: there's ways of doing this, and there's efficient ways of doing this.
My original solution was 8 tools, but it took some 30 seconds to run. Why? Because I used the concatenate function of the Summarize tool. That gummed up all of the works.
I took a peek at other people's solutions and then when whole hog on the multi row tool and it takes a mere second or two to run.
I included both of them in the attached workflow.