No-Coverage Answer
There is no substantive discussion of the Essassani as a species in the Taygetan contact material. The name "Sassani" appears in a handful of transcripts (104, 050, 321, 482, 453) but only as a passing mention in lists of races — never as the subject of any dedicated description, profile, or Q&A. Their appearance, origin, relationship to the Greys, or any connection to Bashar/Darryl Anka is not discussed.
For context, the material does provide detailed profiles of other Grey-related species (see: What are the different types of Grey aliens?) and discusses hybridization as a general concept (347), but the Essassani specifically are never examined.
Searched: All 834+ transcripts, enhanced topic index, themed index 05 (Extraterrestrial Races). Zero substantive results.