I like the bit of world building that Caitians and Betazoids have a shared history. Both are (traditionally) neglected species, and we rarely get this sort of world building that doesn’t directly involve Starfleet.
Anyway, the fact that T’Ana had an uncontrollable and ingrained instinct to hunt them suggests that Caitians and Betazoids were originally from the same planet, which further suggests one or the other left for another planet.
I wonder if their (current) home worlds are in the same system.
It reminds of the kelpien-baul relationship from discovery. If they were from the same planet it would suggest that the betazed-caitian relationship resolved it self at an early stage of development and the kelpien-baul one didn't. Maybe the fact that betazoids are emphatic worked in their favour, and helped them to grow together.