I ended up creating a fix for a fix; here's what was done:For Beasts and Furies, victory animation "happy" now includes sounds from the alternate upgrade of Megera.
For Twilight Witches and Shadow Lords, victory animation "happy" now includes sounds from the alternate upgrade of Night Queens.
https://disk.yandex.ru/d/Mi-qB79JMtd9_QP.S. I have a strong feeling that these aren't the only units missing sounds.