Many enneagram authors associate e4 with poor sensing....the 4 does not have a great grasp of concrete reality. They live in exaggerated emotions, fantasy ideals, romantic tragedies, etc. They interpret the past & present in ways that explain their present image, often a "broken but special" identity, and they imagine a future that will allow them to fulfill their ideal identity.
Naranjo (who is largely credited for developing the modern enneagram system) notes that Jung's Fi description is closest to the e4, but also notes that introverted types who prefer feeling & intuition are most likely to be 4s (that's INFPs & INFJs). Riso (The Wisdom of the Enneagram author) thinks Ni is closest to the 4 description. This suggest INFP, INFJ & ISFP as most likely to be 4s, and that's generally the case. ENFPs are rather common too, but 4 is not generally associated with extroversion.
Both seem to hold the idea that sensing & thinking are not very 4ish. This makes a Se-dom like an ESFP far less likely than an INFP or INFJ to be a 4. The sensing type most commonly 4 is the ISFP, and they often are heavily introverted Fi-dom & can be easily confused with INFx types. Not to say an ESFP could not be a 4, but ExFP 7w6s & 6w7s are often confused for 4s, and an actual ESFP 4 may be closer to ambiversion than a marked extrovert. An ESFP is more likely to be a 4 though than, say, an ESTJ.