I wonder if the supposed correlation between Enneagram 4s and the INFJ isn't slightly overrated. It seems especially with the 4w5, that the main ethos of the 4 goes against the Extraverted Feeling function that the INFJ has as its auxiliary. I mean the interest in collective harmony and conforming to certain social norms; if there's one word that 4s hate, I'd wager it's "conform."
Maybe 4w3's are more likely to be INFJs than 4w5's, but I'm betting that there is a not-at-all insignificant portion of INFJs who might actually be 3's, 5's, or otherwise besides 4's. What do you all think?