my solution involved transforming into date format in order to get the month as a Mon format. My main learnings when doing this - leave everything as a string before using the DateTime tool. I'm guessing you could probably do this as steps in a formula
I created all the months in the Formula tool instead of with the Multi-Row tool like the solution. It was a little cumbersome at the time but looking at the code in the Multi-Row tool, it seem so bad. Of course, this was a small data set.