As to whether there were āgama versions, the answer is yes, but not currently available in an Indic language, only in Chinese translation. In addition to the Madhyama-āgama passage I posted, there is a version of the Assalāyana sutta that was translated as an independent text: Fanzhi eboluoyan wen zhong zun jing, 梵志頞波羅延問種尊經 (Sutra on questions to Buddha about caste from the brahmin Ebulouyan=Assalāyana), translated by 竺曇無蘭 Zhu Tanwulan (*Dharmarakṣa, *Dharmaratna), a Central Asian monk in the late 4th c. Since it expands the discussion a bit, I translate it here. Like the Madhyama-āgama version, it omits the problematic word, unless the word was glossed instead of translated. But it adds an additional equine reproductive set:
《梵志頞波羅延問種尊經》卷1：「頞波羅延言：「我種自說言勝餘種。」
佛告頞波羅延：「有驢父馬母，馬[7]為生子，名是何等？」
頞波羅延言：「名騾。父亦不字為騾，母亦不字為騾。」
「若何以字為騾？」
「我先祖呼作騾，我隨言騾。」
「有馬父驢母，驢[8]為生子，若名為何等字為駏驉？父亦不字為駏驉，母亦不字為駏驉，若何知為駏驉？」
「我先祖呼為駏驉，因隨言駏驉。」」(CBETA, T01, no. 71, p. 877, b29-c7)
[7]〔為〕－【宋】【元】【明】。[8]為生…為＝生子名是【宋】【元】【明】。
Ebulouyan said, “Those of my type (= caste) say that we are better than the other types.”
Buddha replied to Eboluoyan: “There is an ass father and a horse mother. The horse gives birth to a child. What is it called?”
Ebulouyan said: “It’s called a mule. The father is not designated as a mule, nor is the mother designated as a mule.”
[Buddha asks]: Why then do you designate it as a mule?
[Ebulouyan]: “The patriarchs who preceded me called it a mule, and I follow them in saying it is a mule.”
[Buddha]: “There is a horse father and an ass mother. The ass gives birth to a child. Would that be called a 駏驉 juxu (English: hinny)? [1] Neither is the father designated as a juxu, nor is the mother designated as a juxu. So how do you know it as a juxu?
[Ebulouyan]: “The patriarchs who preceded me called it a juxu, so for that reason I follow them in saying it is a juxu.”
—
1. 駏驉 juxu “By some accounts a mythical horselike beast; other accounts give it as the offspring of a stallion and female donkey.” (CJKVE-D). In English this is called a hinny. “A hinny is a domestic equine hybrid that is the offspring of a male horse (a stallion) and a female donkey (a jenny). It is the reciprocal cross to the more common mule, which is the product of a male donkey (a jack) and a female horse (a mare). The hinny is distinctive from the mule both in physiology and temperament as a consequence of genomic imprinting.”
Is there a Skt term for a hinny?