Foremost… In order to answer that question will depend on the persons view of the various Talmudic books, Midrash oral traditions, and position on Yahusha. Do you view him as Ha’Mashiach.

Your own answer to the above will determine your view and position on the question.

To me, it’s not a question of whether to call Him Rab, because He is The Word of Yah. The creator of Heaven and Earth. He is The Word made flesh.

To me, He is more than a Rab. Yet He is the Rab.

John 1:10 He came into the very world he created, but the world didn’t recognize him.
11 He came to his own people, and even they rejected him.
12 But as many as received him, to them gave he power to become the sons of God, to them that believe on his name.

As one who has studied the Talmud and various traditions/writings, there is no requirement that one must be married and have children before being called a Rabbi.

Midrash are simply wildly varied interpretations and opinions of Torah, and only carry the weight and authority of the Rabbi whom gave it. Once a Rabbi of higher authority speaks contrary to the previous prevailing thought, the old opinion hold less weight or then no weight.

While all Israelites are called to be fruitful and multiply… and even Rabbi are encouraged to wife and establish family. Sadly, many of our forefathers of faith died neither being married or having children of their own.