בראשית רבה כב ז
יהודה בר אמי אמר: על חוה הראשונה היו מדיינין. אמר רבי איבו: חוה הראשונה חזרה לעפרה.
Bereshit Raba 22:7
Yehuda Bar Ami said: (Kain and Able) were arguing about the Eve the first, Rabbi Eyvo said, Eve the first died [was already dead].
There are several meforshim that mention her.
As you pointed out in your question, the Midrash of Ben Sira brought in the Otzar Midrashim is actually quite important as it frames what Lilis would go on to become. It centres around Adam and Lilis' dispute over who was to be the dominant figure in the act of intimacy, namely who would be the one to lie on top. ...