

Tam Elbrun and Ariana (from the episode Haven) were outliers and should not have been counted.
I don’t think there’s a real rule. In Haven, Lwaxana Troi says basically anything is possible even for people who probably aren’t telepaths.
What’s kind of wild is all the times Deanna’s empath abilities work over ridiculous distances mainly because there’s a subspace transmission involved. Apparently the specification requires support for telepathy to the extent she can even sometimes understand the emotional state of Ferengi.
Yeah. There were some things that were really sweet about that coda but it sure didn’t make for a coherent and satisfying end to the series that kick-started the modern era of Star Trek television.