Based on my fieldwork experience, including a dialect survey of Choapan Zapotec in 2014, this language is not moribund. The child-bearing generation uses Choapan Zapotec in many Choapan towns, including Lachixova, Maninaltepec (La Ermita), Yahuivé, Yabeloxi, and Jaltepec (San Juanito). Children in these towns fluently speak Choapan Zapotec, though they are part of a shrinking minority. Based on the EGIDS guidelines, I would classify the language status as 6b or 7. Regarding the dialectology of the language, there are two major dialects within the language (though every town has its own micro-dialect): what we could call the Choapan and the Comaltepec dialects. This division is based primarily on sound changes (o> o, u and e> e, ɛ), where the Comaltepec varieties have /u/ and /ɛ/ as separate phonemes from /o/ and /e/, respectively, and the Choapan varieties have not undergone either of these splits.
Based on this information, we will update the EGIDS value to 6b for Choapan Zapotec [zpc] in Mexico for the next edition of Ethnologue.