"AFAIUI" is nowhere even close to as common as your other examples. I have never encountered it before, and Google Trends doesn't even register it in a comparison between the others.
Trends isn't the best for this as it's search results not occurrences so really all this will show is the number of people confused by the term for weird contractions like this. "AFAIUI" could theoretically just be completely understood by the community using it.
Oh, I understood what you meant, I was just providing an additional data point for this particular conversation in response to what you were saying re: search queries vs. results.